I think that it can be perfectly reasonable to be in touch with an ex...one of my ex's is a good friend now, and there's nothing romantic going on there. But we're not even talking about a connection here, simply the fact that she's not 100% unreachable by these ex's.

To be honest, I think you need to get over it. If anything, the fact that she has the ability to contact these people and choses not to should give you more trust in her than if she was out of touch simply because she didn't know how to reach them.