Lately I have had the same issue with my husbands girlfriend.. She also has been less than honest about a few things that I have found out about this last week, and we have had much the same type of conversations. I am not thrilled at all and having some trouble trusting her and he says he doesnt like it either but can understand why she has said the few lies she has. But I have told him I dont trust her and I hope she can straighten up because trust is everything to me and I dont trust her much right now.
He says he has no problem telling her that he will not talk to her again but also seems to give her more lee-way.
For the moment I am waiting it out for a bit and watching closely to see what happens and if she isnt more honest he will break up with her.
I've had much the same trouble as you have, with wanting to like her and wanting to get along with her, and I know this puts my hubby in a tough position.