she slept with bartender during that time, but I can forgive, we weren't together
Huh? There's nothing to forgive here, you two were not in a relationship and this sounds ~~parasocial~~ co-dependent. I recommend seeking therapy focusing on DBT if you want to manage what you consider are intrusive thoughts (disclaimer not a mental health professional). Also, if you two are talking about marriage then you should have a conversation about relationship boundaries before anything else.
Also recommend spending less time on the phone together and more time on dates. Phone calls are not a substitute for spending time IRL with other people.
