You're lucky at least you're with a guy who loves you! I could be pregnant and i don't even know who the father could be! definetly keep the babby, as you are getting married your parents obviously love you, and so dose your boyfriends family , I'm sure the new's will come as a shock, but not a supprise, if they knew you were dating the guy and then going forth to marry him, they must have known you were having sex, these thing happen , just take resposibility for them, tell both set's of your parents together with youre boyfriend , It takes two you know! He's equally to blame in this, its not your fault!!!
Best of luck!!
And god bless X