My own trust issues

I was in an abusive relationship for nearly 8 years. I escaped, barely but that's another story. I was single for ages. (Over 2 years without sex. It sucked. I don't recommend it at all) fast forward. I am in a wonderful relationship! This man is incredible! But. Omg. I have trust issues. And there's absolutely no reason to have them! He's never lied to me never snuck around. Never chatted up other ladies. Always attentive and kind and loving. Yesterday he had a training session he wanted to go to (we both practice martial arts a lot) he went but the whole time I was wondering what was really going on.

Turns out it was what he said it was

Multiple people posted photos of this training session. It looked great! And there he is smiling! Beaming! Truly enjoying himself!

I feel like an awful person. Why cant I shake this?

Is it from my past relationship?