I am also so lucky to have a family that are amazing, we have our down points but if something is wrong we talk about it... it's normally between me and my sister lol, but we are also more like best friends than sisters!! As for OH's family, I am also very lucky there too, I get on so well with them, although I'm not too sure OH's mum has taken the news well... she hasn't congratulated me and won't tell OH's stepdad.. oops!! but I know she'll be ok once she get's her head around it and if not... tough!!
I couldn't imagine what you are going through Jill, I feel for you so much as it must be an awful thing to have to go through and must drag you down so much, but, as Katie has said you don't have to talk to them, as awkward as that may be, you have enough going on in your life without having to cope with their crap!! You are an amazing person and don't let anyone else say otherwise hun xxx