I don't know what to do

So I have been with my boyfriend for over 4 years. We broke up for 5 months to take a break from each other and we got back together the 1st of April and have been good since.  I found out I was pregnant towards the end of April, thinking that we knew when I had my last period that when I went in for my first OB on June 9th we thought that I was 8.5 weeks but we did an ultrasound and I was 12.  The doctors still believe that it is my SO because they think I conceived anywhere from the 1st-3rd of April but I had intercourse with someone else March 24. Therefore if I conceived then I would be further along, but the doctors won't do a paternity test until the baby is born, and my SO won't tell his parents until he knows it's his, or if he does tell them he is going to tell them that he is not sure if it's his and that will make me look and feel like crap. I just don't know what to do. I am due December 23 and will be 14 weeks tomorrow.