How can someone be such an asshole

So yesterday I found out not only has my ex left me 6 weeks ago, after us trying for a baby for a year and a half and 4 miscarraiges (I'm also now pregnent 12 weeks today we haven't even announced it yet), putting an offer in for a house and him buying an engagement ring then dumping me 2 weeks later, I now find out he's been seeing someone else. From work. I have honestly never felt pain and betrayal like it. I feel physically drained on top of I can't keep my preggo emotions in order as it is but this has just tipped me over the edge. You think you know someone ey? Asshole.