This was a question I received in response to this essay I wrote last month about my experience in (and coming out of) an an abusive relationship. I'm sharing my answer here, with permission; I don't think my advice here is necessarily novel, but I did put a lot of thought into this and if it goes on to help any other folks, I'd be very happy for it.
Oh boy, great question— I feel like I could write a lot on this. I've tried my best to distill some thoughts down to a few concrete things here, but mind you I really can only speak to my own experience, and of course, YMMV.
But for what it's worth, my advice is this: First, to start thinking about things you couldn't have done with your partner around. Was there anything you ever enjoyed that they never really had any interest in? Anything you wanted to pursue that they didn't really approve of? Places you wanted to go, things you wanted to see— hell, even a kind of person you wanted to be— that just didn't ever quite fit into your relationship? Even if the two of you shared most hobbies and general likes and dislikes, I bet you can still come up with a few of these items. Then... well, try leaning into them! Go ahead, be self-indulgent about it! It's a lot harder to wish someone else were around if you know that them being around would mean that you probably wouldn't be experiencing the joy you're having in the first place. (Realizing that your partner may have been subconsciously— or perhaps even consciously— robbing you of joy may also bring on feelings of frustration, anger, regret, or resentment. While that may sound unpleasant, this is all very normal and it's healthy to be processing these feelings, too.) Consider this an opportunity to get back in touch with your own self, or your inner child, or however you wish to conceptualize this "personal nature" we all have. I've only got my own experience to back this up, but I think (re)discovering our own personalities is a critical part of recovery after codependent experiences, where we tend to wrap so much of our identities in other people's wants and needs.
Second: I think it's absolutely fundamental to the human experience to be sharing. Like, certain events or moments may bring us individual joy, but sharing the experience with others is what gives them any meaning for most of us; it's hardwired in. This is all to say: it's a very, very relatable feeling you're describing— that, "This is nice, but god, I wish X were here to see it too..." And, the truth is that this feeling of wanting to share— with someone; it won't always be your ex-partner and may sometimes not be anyone in particular at all!— that feeling isn't ever going to go away. So what do you do about that? Well, you've got to find some new people to share with. Easier said than done. I think the hobbies or activities you've already thought about from Step 1 make the best place to start: for making adult friendships, there simply is NO better route than finding community in shared activity. Rec sports, theatre troupes, activist networks, outdoors groups, literally any kind of class— this is all gold. Not everyone in these groups will be your cup of tea, and you may have to try several before you find a good fit— but chances are, you can meet at least one or two people in each new circle who will at least be fond pals, and maybe even deep lifelong friends. This can also be a great time to reconnect with old friends you lost touch with while caught in your relationship, too. You may even already be doing this, in which case my advice then becomes: keep doing it, and don't give up!! (Side note: I'd avoid trying to make friends on dating apps if you can; if you're looking to date a little, even casually, the apps are fine! But they tend to cast a weird shadow on "platonic" connections that just make them less tenable for making friends, IMO.)
The other great thing about putting yourself around a lot of new people, I've found, is that it teaches you entirely new valid ways of being a person that you might be interested in trying for yourself. Seriously, for years after I broke up with my abusive ex (and even sometimes still to this day!) I would witness two people interact— one stranger approaches another in a way that's not so awkward; two people have a healthy, loving fight; a coworker approaches their boss in a surprisingly tactful manner— and I would go, "WAIT— YOU CAN DO THAT?!" You'll start to see so many new modes of simply Being that you can learn from, and in my experience, this learning process is not only rewarding but downright fun. And again, it's exactly the kind of thing that can help in the post-codependency recovery stage, where your body and brain have probably been conditioned to think that only very certain social and emotional patterns are available to you, based on the way you and your partner always interacted and what either was or was not okay with them.
Things aren't going to change overnight; certainly, you will still be hit by surprising moments of grief where it's going to feel like none of your friends, either old or new, compare to that one, special person you used to have in your life. That's okay— give it time. And give yourself plenty of attempts. As you process your emotions more and more— especially if you did experience abuse from this partner— your feelings will also naturally start to change. You'll start to see that ex-partner in a different light, and you may realize you actually don't desire to share much with them anymore. It may also help to really interrogate what the component parts of your grief are. Is there frustration from feeling like you wasted your time with them? Listlessness from feeling like your life was all planned out, and now you have no idea where to go next? Resentment for the emotional scars they may have left you with? Longing for the better parts of them you were fond of? Each of these feelings will need to be dealt with uniquely. If you are looking to force a faster change: it's true what they say, moving to a new city or finding new roommates or switching jobs or other similar big changes really can do wonders in helping to get over someone and find yourself! But of course, those are pretty drastic measures and they aren't necessarily feasible unless you were, for example, already planning on moving soon anyway. But, potentially something to consider.
Finally: understand that everything you're feeling genuinely is all natural and normal and part of the process (really). If you're experiencing any guilt about how it's taking "too long" to recover or how you "shouldn't" still be feeling the grief that you do— well, do your best to give yourself some grace and kick those guilty feelings in the face when they show up. Not only is it okay, it is good and necessary to grieve; your body needs to feel those feelings (and you might be feeling them for a while! though it will be less and less as time goes by). Right now, your biggest concern is just making sure that you're grieving in healthy ways. That health component is critical and I can't overstate it. If grief is leading you to alcoholism, self-harm, anything of that ilk, now is the time to recognize it and seek appropriate help. But many other coping mechanisms are wonderful and even allow for a little recklessness in safe and healing ways: cry it out! make a playlist! bury some old notes or throw 'em in the ocean! travel, dance, kiss someone you fancy, cry some more, let yourself be mad and upset, make peace and do it again. Start therapy if possible and you haven't already (I know the U.S. healthcare system is an absolute nightmare and this is not always an accessible option, but I truly can't stress how helpful the right therapist can be if you have means of finding one).
It sounds so fucking trite, and I wish I could be more helpful than this, but a lot of this business really does boil down to: learning how to "love yourself." That's a lifelong process with no endpoint, but just because it's an infinite path to travel doesn't mean great and tangible progress won't be made. I think reflecting critically about your own emotions/personality/hobbies/goals/etc. so as to know yourself, and pursuing those needs and desires with the help and company of beloved friends so as to love yourself— well, I'm greatly overgeneralizing, obviously, but those are the basic principles which have really helped me. At the end of the day, it's not so much about putting yourself out there as putting yourself in there— into the world, into the thick of things, into the great and beautiful mess of humanity (regardless of who may or may not be coming with you). If you can do that, I promise, you'll be in great shape. Few griefs ever fully go away in life (and of course, what even is grief, if not...) but, if we cannot move past them, then we may at least grow beyond them, such that what was once all-consuming is now only a small knot in the ever-expanding circle of our lives.
. Its working title is The Tenderer. Broadly speaking, it's a speculative fiction book about gender, [abdicating from] power structures, and what we do with love when it seems like there's nobody left to give it to; think Ursula K. Le Guin meets Phoebe Waller-Bridge's Fleabag. It's also got super weird-ass brain stuff, haunted-ass train monsters, gay-ass romance, and cool, smart-ass robots (everything the body needs!) in case any of that sounds up your alley.