He had two children from another relationship, whom I knew about - then we had one, and he left when our child was 1, and got married to someone else. We haven't really seen him since, but I have just looked up his address on google and found lots of stuff relating to a teenage boy who lives with them, (new woman had three children I was told - this is one of them) and the pictures of him are the spitting image of my ex.
He has a blog which I did look at, out of curiosity - he seems like a lovely young man - and he mentions his father having had a wedding at a certain location. Now whether his 'father' is referring to the man whom his mother was previously married to, or my ex, I cannot tell, but they did get married there so it all seems a bit odd.
I am now wondering if they had a child together long before I even knew him, and then he went back to her and married her, and is now living with his elder son.
Perhaps it isn't my business. I am a little shaken though, and unsure what to think.