how do you deal with "trust issues"?

To me, trust will happen once communication is in place. If there's anything that bother you, you need to speak out and clear it up with the other before it's too late to solve. If the other had broken your heart, I would ask you whether you still love him/her and want to be with him/her or not. If you decide to stay in relationship with him/her, then you need to face the reality that it might happen again or unless you need to talk to him/her to find out the root cause of why he broke your heart and what can be done to prevent heart breaking situation from happening again. And then you need to overlook whatever that had happen in the past and move on like nothing had happened.