he's got a kid!

B
So I've been seeing someone for a little while and it's really full on, but they've just suttley dropped in that they have a child they never see and they haven't for 7 years as it was a different life etc, 
Like what ?! What do I do? I'm pretty confused. He didn't tell me and how do I feel knowing he doesn't see the kid?!:/ help. What do I do?