Need advice on broken trust

My boyfriend broke my trust about 4 years ago. I love him and I want to work through this so we can have a happy/healthy relationship again. Even after four years I still struggle being able to trust him. I haven’t found a way to work through it to where I’m not tearing myself apart. I get upset that I still haven’t gotten over it and I need some advice. I’ve tried accepting the fact that it’s in the past and it can’t be changed now, him and I have talked through it and I’ve been in therapy to work on this. Does anyone else have any other tips that may help?