How do I tell my boyfriend of 2 years that he might not be the father?? and how do I tell my family?? They are really judgemental... should I wait until after the baby is born to tell everyone??

Tough call. You need to tell your boyfriend and you need to share this with there family. Why would they not be judgemental. Do you think it is right sleeping around on your boyfriend? People makes mistakes but you made a huge one and you need to be honest about it and face up to it.

As far as could be the father or might not be the father. The only safest way to find out who the real father is, is after the baby is born. It sounds like it is important for you to know, it is important for your boyfriend to know, and it is good to know for the child you are bringing into the world.