I think I’m a bad partner

I’m having a really hard time with a belief I have that I am a bad romantic partner. I had a volatile marriage with my first husband and now I’m engaged to someone else and we are struggling. He has told me that I’ve pushed him away with nagging/being controlling and grumpiness and even weight gain. He thinks I’m not the person he met. I can see how I also was controlling with my first husband. So now I have a model that looks like this:

C – romantic relationships
T – I am a terrible partner
F – Self-loathing
A – hate on myself, don’t process the emotions I’m having around the relationship/avoid/resist them, gather evidence of all that I’ve done wrong in my first marriage and this current relationship, try to get my partner to see my side or tell me things are good so I can feel better
R – I’m a terrible partner

This isn’t the model that’s running though when things are good (at least in my eyes). Yet I’m still apparently not showing up in a way that my partners like. And when it’s pointed out, I agree that I don’t like how I’m showing up. But in those times when things seem good to me, I don’t realize that my actions are out of alignment with who I want to be. I could use some help in how to sort this out for myself.