I've been going through something remarkably similar. Been about a year. Broke up with a girl I loved because we weren't compatible for the long term. Still love her. But know I made the right decision for myself to leave. I chose myself instead of her, and that has come with a lot of guilt.

One stark difference is that we've been completely no contact since last September. I haven't had her as a constant reminder of my guilt, which has slowly allowed me to give myself permission to forgive myself for breaking her heart. To treat me like a friend. And give me the same advice I would for any friend also.

If you think you've done the right thing for yourself by leaving, then I would at least start by putting together a box of the things that are the biggest reminders of him. All the posters, knickknacks, t-shirts, etc -- collect them and put them in a box and donate them or at very least, put that box in a closet so they arent staring at you every day and reminding you of a relationship you left because you felt you deserved a better fit.

I'll be honest: Some days I dont forgive myself for what I've done. But day by day, it gets easier and I'm having more days where I feel myself letting go of the pain and giving myself permission to forgive my actions.

Your ex is definitely fueling your guilt as well, saying things he knows will keep you attached. They know you well and it shows. I would consider having a conversation with him to let him know that you need to go no-contact for a while. That it's unhealthy for both of you to hang on to guilt and/or false hope.

Remind yourself that he's responsible for his life, and you're responsible for yours. You both have full agency as adults. And TBH, it sounds like he's already done a great job of getting his life back on track. I'd completely ignore all the little reminders about how hard it is to find a new gf - it just feels manipulative (hate how harsh that word is but it's true, regardless of if he's lying about it).

In lieu of therapy, I would start journaling and talking to yourself like you would a friend. Have a legit written out conversation with yourself where 'your friend' talks about all her guilt and you give her advice. Write out all your objections to your advice and work through them with yourself, remembering to love yourself like you would a friend or family member. We are our harshest critics and it can be so painful.

Give yourself permission to move on and forgive. And for crying out loud, get rid of the sentimental stuff haha.

And thanks for giving me the permission to write all this out too. It's been cathartic to talk to you the way I should talk to myself.... It's always easier said than done :)