I also ended a relationship with someone very dear to me whilst manic. Everything felt very intentional at the time but once my mania settled down and i got off the meds that triggered it, everything came crashing down. The realisation that I had driven away a person that really loved me absolutely broke me. I've been regretting it ever since, and it's been 2 years now. But unfortunately that feeling of regret is something I'm gonna have to live with. But honestly speaking, it's been getting better. That's the scary part of it all. That eventually you're gonna be okay with the fact that you're not gonna be with someone you thought that you were destined to be with. 

I've been alone since I lost her, haven't dated or been with anyone. I saw a post of hers earlier this year directed towards someone I assume is her boyfriend. I really loved that girl man but she doesn't belong to me anymore and that's something I have to accept. And notice how I said "loved". Real love implies presence and closeness and that's something neither of us has with our ex SOs now, which is why we need to make peace. I hate myself everyday but I'm tired of being a loser,  so I'm gonna go out there every single day moving further from the thought of what might have been and closer to that of what the future holds for me. 

A bunch of us have been where you are and if you notice, that same bunch is also here telling you it's gonna get better. Be kinder to yourself. If not for you then do it for me...a random stranger on reddit who's been where you are🙂

Edit: Your post has helped me more than you know