Wow. Neither one of you has behaved appropriately, as far as I'm concerned. Asking her to compare your dates to other dates is basically asking her to compare you to other men - so you got what you asked for. I would have taken it one step further and talked about how amazing the sex was, simply out of spite. Yeah, I can be immature at times too, I know. But beyond that, no I have never once searched through anyone's things. I always rationalized it that if I have to search, I might as well break up now because the trust is gone. And there is no point if there is no trust.
Also, if something really bothers you, she shouldn't contribute to it. If my INTP bf was so bothered by my friendship with another person, I would cool it with that friendship. No one is worth me having an unhappy home. But then again, I know my bf would never ask me to do that unless there were some real reasons other than some vague unsubstantiated "jealousy". The point is, assuming you are not just jealous of every man she talks to, if her friendship with him bothers you and she continues it, then she's telling you exactly how high you are on her priority list. It's as simple as that.
I think a lot of the problem stems from conviction or lack thereof. I have a lot of ENFJ friends that never quite mean what they say. They will break up with a girl and then try to get back together a few months later. They will tell a girl they love her and then confide to me that they fell out of love. In my experience, we NTs don't do that. We don't lead with our feelings. When it's over, it's simply over. We broke up for a reason, so it would be irrational to attempt a reconciliation. So you may be worried that they will slip back into whatever they had, but she is looking at you like you have 2 heads because she already told you that she wouldn't. So either you trust her or you don't. And either she respects you or she doesn't.
I don't know. In my experience, INTP women have trouble with boundaries. Hell, INTP's in general do. This leaves them vulnerable to fucking up. On the other hand, they can be trustworthy. You just never know which INTP is going to go which way. I think it's similar with ENTP's except ENTP's feel more bound by society's rules.
Synarch said it all. I also feel that INTPs have boundary issues. When they become close with someone, they don't know where to stop. The less evolved ones find themselves in weird situations that spiral out of control before they realize it. They seem to have no sense of how society works. I get a hug that is a little too inappropriate. Or a well meaning gift executed in a creepy manner. One INTP guy I know bought a gift for his girlfriend's sister and snuck into her bedroom and left it under her sheets. That is the definition of creepy, imo. No boundaries.
And I get the impression that they are scared to say no to people. So if they found themselves in an awkward situation, they would most likely roll with it rather than try to stop it - just to avoid the confrontation. But I don't believe that they have dubious intentions. And I don't think they are that way with those that are close to them.
As far as INTPs being happily committed, I think it just depends on the person and their relationship, just like everyone else. Mine seems pretty happy and he embraced each level of commitment like it was the most natural thing in the world.
(Are you the same guy that made multiple posts about an INTP girl a few months ago, a girl that wouldn't commit and broke up with you and freaked out when you had sex with someone else? If you are that same guy and she is that same girl, I think the two of you probably are not very well suited. At all.)