@DollyDaydream70 I'm so sorry to hear you've been through that. I can understand 100% how difficult it is to trust again after having such a negative relationship. It makes everything difficult.
Both my partner and I were cheated on, and mine was emotionally abusive (never physical, thank goodness), so it was a complete nightmare when we first got together, as we really liked each other, but we just couldn't relax, trust and enjoy, as we were just convinced something would go wrong. After almost 3 years we're pretty much there - but that doesn't mean I don't sometimes worry when he's texting the same person a lot. Add to that he turns his phone screen away so I can't see (because he knows it upsets me sometimes even when it's perfectly innocent, and he thinks I don't notice the slight movement) and it makes it worse rather than better!
Just a note about what you said about the girl being disrespectful towards you. I'm not sure if that's the case. Obviously I don't know them, or their relationship, or their intentions .. but most of my friends are/were male, and one by one I've lost them all as they got into relationships. I would have thought nothing in the past of phoning them for a chat, or asking them out for a meal or for a coffee, or popping round to see them.
Nothing sexual, no attraction. Yet, all but one of their girlfriends has put a stop to the friendships, leaving me pretty much with no friends. It was incredibly difficult, but at the same time I can see it from their perspective. I think you're worried more because you're not sure, and you don't know what they talk about or get up to when you're not there .. but speaking as someone who has lost very close male friends when they got into relationships, I don't think it's fair to put a stop to an innocent friendship. And if they do have a truly amazing, innocent friendship, it would be a big loss to them both. We all need friends, it's not healthy to stop innocent friendships because of a partner.
The only problem is that you can never be 100% sure - in your own mind - that it is innocent. And the distance - plus your past - makes all of that worse!
:(