Cheated & unsure of who's the father?

I'm currently 18wks pregnant and I'm unsure of who the father is. My husband and I had got into a huge fight over his infatuation with the next door neighbor. The night after I went to meet up with this guy that has been at me for a long time. Him and I had unprotected sex. A few days to a week later my husband and I made up and we had sex. Not too long after about 3wks  I found out I was pregnant. I tracked my sexual encounter with glow between the other guy and my husband and it's too hard to tell who's baby I'm carrying. Of course the other guy says he doesn't want any more children and my husband is nonchalant about the whole pregnancy. My husband had no idea I cheated on him. I'm confused on how to handle this before baby comes out. I want to do a DNA test with other guy but I don't want to make it obvious to my husband that it's a possibility the baby isn't his. HELP!!!