If you're posting on here asking questions like this your relationship is obviously not strong enough to have trust in this situation.
However, you don't seem to have the strength to put your foot to and make sure you get what you want either.
So you might as well just suck it up and live with it. From what I'm seeing here if she did sleep with the guy and came back you'd probably forgive her anyways. If you wouldn't, then you better start telling her what you want out of the relationship right now.
however if you're going to keep going with the wishy washy middle of the road attitude then I guess the only thing left for you to do is to pay for her hotel room....and hope she uses it.
