My boyfriend only stayed with me because he thought i was carrying his baby.?

Me and this boy have been on and off for 2 years, and a couple of times we've got really serious and close. we've been out propley for periods of time but end up ending it and then making up. this time we took it to far and had , we wernt going out but ended up going out when he found out i might be pregnant (iv now relaised) now he knows im probley not his dropped me and slags me off and humiliates me to everyone and makes a complete fool of me, i dont know what to do?