and to answer the question (sorry), I would like to think that I would be savy enough to know that someone I was that close to was hiding something before I got down the road of living together/reproducing.
However, if I wasn't and did get caught up like this, I think, sadly, I would quietly take the children and leave one day, leaving a note of explanation and asking for him never to contact me again. I may even go as far as seeing my MP an dasking them for identity change so I couldn't be found, depending on how in danger I felt. But I certainly would not be able to trust that person with my children to any length at all.
Maybe I'm a bad person, who knows, but I would also worry that my child might end up doing something awful if left in contact with the father. I don't know, it would just be something in the back of my mind.
I feel all sad now. I'll have to go into christmas section and read all the christmas questions to cheer myself up.
:-(