My girlfriend has a big history with guys and says she’s changed but I have trust issues and always thinks she’s cheating. What should I do?

A relationship is healthiest when centered on trust and communication. It seems she has been open about her history which is a good sign, someone who intends to continue such behaviours is unlikely to air out their dirty laundry in such a way. If she has given you no indication that she is being unfaithful, if there are no signs and this is all just based on what she has told you, then pressing these issues can cause problems in the relationship. It's understandable to have concerns in a situation like this. If you can create a space where you can voice these concerns in a non-accusatory manner it could be beneficial. It sounds like something that will require some work but the longer you're together, the more you communicate, the stronger your trust will be.

what I really feel is if she is sincere towards you and definitely like you then why would she cheat on you. I understand your insecurities. But with trust issues, relationship will only get worse. As long as you have not caught her red-handed, there is no reason for you to not trust her. I think it's better to believe in yourself and your partner rather o believe others. If she really likes you and she is sincere towards you then I guess she is not cheating on you. Believe me One partner can change whole life of a other and make the person to change from player to committed. Think carefully and have any questions come and find me here

It can definitely be very hard at times for us to trust other people, even boyfriends or girlfriends. I cannot offer advice but I am here to listen to you and what you want to share and try to help you find the right way for you. Are you comfortable being open with your girlfriend and talking about some of your feelings and trust issues? Do you think this is something that may make you feel better about the situation? Also, would you like to maybe explain what is it exactly that makes you feel like she may be cheating?