Needing advice from dads... Ex fiancé and I are getting back together but I am pregnant

I am hoping I'm putting this in the correct category. My ex fiancé and I have been split up for about 6 months. We've tried to work it out off and on and had a lot work through. I briefly dated someone else and then my ex and I finally realized that we could work out our relationship and that we belong together. As we are in this process, I find out that I am 7 weeks pregnant with the other mans child. Now my ex is not sure if he will be able to love this child like his own and to really be there for me. I completely understand where he is coming from and he truly does want to make this work. Also, it does not look like the other man would really care to be involved, which my ex does think would be better for all of us. 

I am embarrassed by the situation but we are really looking for advice on the situation. Has anyone been in this situation or one similar? Thanks in advance for your help!