Prenatal paternity testing

Anyone have any input on this ? how accurate were your results ? I'm scared to death the father of my baby isn't my husband. We were separated but still sleeping together having unprotected sex... But around the same time I got very drunk and had sex with a friend. (Please don't judge, this was a very VERY rough time for me.. I know I'm an idiot) The friend never finished inside of me. We were so drunk it was just awkward and a mess.. But my husband and I had been having unprotected sex for about 8 months with no luck of getting pregnant then it just so happens after sleeping with someone else.. I got pregnant. My husband and I are now back together and working things out.. But I just can't help but wonder if the baby is my friends? Looking back I was ovulating during the time I had sex with both of them. My husband and I have said we don't want to know what went on during the separation.. But I just need to be sure he is the father. Our families are so excited and we are so excited but if it later comes out that the baby isn't his, he will be crushed.