How do I ask a guy about his past if he hasn't mentioned it yet? Is that my right?

I met a guy on an online dating site in early January, and we talked for about a month and a half before meeting up. We finally went out this past weekend and really hit it off and have talked every day multiple times a day since. He asked me out again the following day, but I was stuck at work. Since then he’s talked to me about another date, but we haven’t set a day (the date was only a few days ago).

When I had originally seen his online profile – I noticed that he mentioned he said that he had kid(s) and that his longest relationship was 6 years. It didn’t bother me too much then, he is 32 and I figure that at this point that’s going to be common. (I’m 26).

I’ve always tried to delicately bring it up – dancing around the question without being invasive or nosey. He’s told me that he wants to ‘begin a family’ at some point, etc. It’s starting to bother me that he hasn’t even so much as mentioned his past. I’ve brought mine up in hopes that he would as well, but to no avail. So I finally decided to do a little Facebook research and came across an old page that he had, which in turn connected me to his (ex?) wife’s page and a picture of their son. All the pages haven’t been updated since early January 2013, as far as I can tell.

Is it my right to ask him about his kids/past relationships? And how do I do that? (Without sounding like a stalker of course). My gut reaction is to give people the benefit of the doubt and I automatically jumped to the conclusion that maybe something traumatic happened and he’s possibly not ready to talk about it. On the opposite side of the spectrum, he could still be married.

I found this all out last night. He’s messaged me since, but I can’t find it in me to be calm and collective so I put off messaging him back until this morning, and I’m not sure what to say being that I’m confused and a little angry. Having an (ex?) wife and a child are a big deal and I feel like that’s something that someone you’re possibly going to date needs to know. It would not have been a big deal if this was brought up in the beginning. Just as a side note – he is incredibly sweet and mild mannered, and he is a bit of a geek so from what I can tell he doesn’t seem like the cheating type (is there a ‘type’?). He has emphasized that loyalty is important to him.

Help!