Would you consider your past relationship an abusive relationship? I wasn't in it, but it sounds like it to me.
You were with her for a long time, and it can take time to get past that. Have you considered therapy?
Maybe it's something where you just aren't used to someone treating you well, or you don't think you deserve it, or don't know how to have good sex, or know what it feels like, or how to trust in a good relationship, but a therapist can help you work through all that.
It's really hard to be in a relationship where you aren't appreciated. It affects you in a lot of ways. If there is even a small chance that you think you don't deserve better, please know that's not true. I know you came here asking about sex, but you have to heal first in order to have good sex.
And one more important thing, my last relationship lasted for 8 n half years. I gave my all love. N in all this years she just made me lose only two times. I was deeply in love with her, so just gave my 100% in every ways.