Fucked up logic

A och H har varit ett par relativt länge. A's ex-husband har just varit i stan, har hookade med A's och H's kollega/vän Cam.

H: "You're divorced, why aren't you fine with Cam sleeping with him?"
A: "Well for the same reason you aren't fine with him still being in town."
H: "If everything is over with him, why do you care who he sleeps with?"
A: "Why do you care that he's still in town?"
H: "I don't care."
A: "Obviously you do. If you were 100 per cent certain of me, you wouldn't care. But you do."
H: "If you were 100 per cent certain you didn't want him, you wouldn't care that Cam slept with him."
A: (Deep breath.) "You don't trust me."
H: (Deep breath.) "Saying that... means you don't trust me."
A: "How can two people who don't trust each other get married..?"
H: "I thought we did trust each other."
A: "Yeah I did too... Two people who don't trust each other shouldn't be together at all."
H: "You really think that?"
A: "Don't you?"
H: "Yeah.. I do.. I actually do think that.."
[...]
A: "You know, all you had to do was trust me."
H: "Hey, you're the one that's leaving."
A: "You're the one who isn't stopping me..."