Help me, my fiance is not supportive

I just found out I was pregnant yesterday. I was freaking out and told my fiance and after about 2 hours of him crying, he told me he wasn't ready and he was scared and that he was afraid he would let his own selfishness ruin our relationship (ie. He is scared he might walk out - not that he WOULD but that he might)... He wants me to get an abortion. I can't do that. But I don't want to ruin what him and I have. We have been together for 5.5 years. We have history. Will someone please talk with me about this. I wanna keep my little tomatoes seed but I wanna have everything okay at home as well.