Please answer! how can I get my parents to understand my relationship?

Hi im 22 years old and I am bi ually. When I was 19 I told my parents and they were totally fine with it. Last year I started dating a guy "Josh" my parents LOVED him. But they didnt know that "Josh" was also bi. We have experimented in our relationship and tried having 3 sums to allow us to have both ually desires but he was very uneasy with seeing another guy touch me. So we came to the understanding that as long as were open with each other it was ok if we seen other people (me seeing girls, him seeing guys) We are always safe and for him it is mainly oral play. This doesnt happen regualarly, its has only occured a few times in our relationship. Over christmas he went out for drinks with a friend and got really drunk and kissed a guy, my brother in law just happened to be at the same bar and seen the whole thing. MY brother in law came home and told my sister and parents. The following day they came to my house to tell me that Josh was cheating on me and was gay. I tried to calmly explain the situation but everything got really out of hand. My dad was mad as hell calling "josh" a fag, freak and a walking STD and my mom cried the whole time. They told me that if I conitued with the relationship that I couldnt be part of their family and left. I thought it would all blow over once things settled down but it didnt. Its been a few months now and they still wont talk to me. I found out I am 12 weeks pregnant and want them to be here for me and my baby , but how can I get tem to talk to me>