He hates me..

My SO and I broke up bc he never spent time with me and showed any love or affection. We work together so it's kind of awkward but anyways here I am 31 weeks pregnant and I see he is adding his ex gf on Facebook who I must add he was very much in love with before me. I'm heart broken bc I ALWAYS knew in the back of my head they stayed in touch and they'd get back together and not just that, why add her when I'm pregnant and I'm already emotional. This is just so messed up