Why do guys hide information about their exs?

Kimberly,

May I ask why?

I'd have a very hard time to accept any justification as to why she decided to contact my ex. Besides if the ex holds a grudge towards your boyfriend then the situation can become very explosive very quickly.

If you do proceed then just make sure that the end justifies the means.

Definitely this is dangerous territory.

You know the saying, sometimes knowing too much can be worse than not knowing anything at all. And even so, your guy is now focused on you. If the ex is out of the picture, why drag her back in just to feed your curiosity about their past relationship that now remains non-existent?

Just be careful. Also, it may make him lose trust in you, where he may see it as you sneaking around behind his back. If you really are that curious about her and their past relationship, you should just ask him directly.

There's no reason to do that. She's gonna be weirded out, it'll get back to him, and you will look like a freak. Not trying to be rude, I'm just keeping it real. =)

Very Dangerous and he will not be happy. Give it some time and he will eventually tell you all about her. But, I would not suggest contacting her at all.