Struggling with letting go

I have been working on coaching myself about a relationship that I was in for 2 years that ended a couple of months ago. I’ve been coached on different aspects of it multiple times in the 20 min sessions. But I keep going back to the same thoughts. That it shouldn’t be this way. That we are perfect for each other (and it’s only external factors that prevent us from being together). That I will never connect with or love anyone else the way I connect with and love him. I’ve tried to just accept the sadness and loss and carry it around but it’s so heavy. I’ve tried to see that this happened for me because we actually aren’t right together but I don’t believe that. I’ve tried to think that something better awaits but I don’t believe that either yet. I work with him and love to see him and we still have a relationship in some ways. But the constant reminder of not really being with him is difficult. And I’m super resentful and jealous because he went back to his wife that he was separated from.
I recognize all the thoughts. I know I’m causing the pain. But I just keep looping.