He also has a girlfriend now. I've never met him.
Most Helpful Girl
You could trust her, yes. Only if she gives you a reason to think otherwise then you should be worried or watchful. Think of it this way... If you were with someone and you both decided it wasn't working out, that you were better as just friends, would you stop speaking to them just because you got a new girlfriend? As long as the person does not overstep the boundaries of friendship (try to push themselves on you or something) there would be no reason to stop talking to them. You need to focus more on your confidence. Be confident that she is with you and you know you are good to her so there is no reason for her to be unfaithful. At the same time if you ever begin to feel suspicious that something is going on, tell her that you expect her to be honest with you if she ever does want someone else. Believe me, it's better if she tells the truth and it hurts and you can move on, than for you to keep thinking there's something going on and hurting all the while. I hope this helps :)