Emotional single Mommie

I am currently 24 weeks & thought I was past the emotional stage,but clearly not 😔 I have been a wreck this last week and I guess everything is hitting me. I am so beyond excited about my little boy due in July as is my family, however I have not heard from the father since I was 8 weeks. We were together over a year & engaged. We ended things right before I found out & things were never the same since he did not hesitate to move on (baby or no baby). 
I haven't put much thought into it but I guess it's time to accept that he will not be around. I keep having very vivid dreams about him (the father) and it just hurts me even more. He is the type of guy that wanted a child more than anything & it just amazes me he has turned his back like it's not even happening. I am okay with being a single mommie as I have a fantastic support system, but what do I do when my baby's father tries to walk back in? I couldn't handle it now much less 5 years down the road! Single mommies, I need advice & guidance 😥