Hello there, hopefully you will be able to give me your opinion based on my situation,I have been worried this whole time about paternity of my unborn baby.
Here is my situation: My lmp started Nov 17 2007 and I have about 22 day cycle. I had a casual unprotected sexual encounter with #1 on nov 2 2007. I started having sex with #2 from nov 8 2007 on. After my period ended, #2 (which is my husband now) started ejaculating inside me, and on Dec 21 2007 I found out I was pregnant. I just wanted to know if it is possible that #1 could have resulted in this pregnancy. I went for a trans vaginal ultrasound on jan 14th 2008 and it showed I was 8w and 3days pregnant, with due date August 24 2008. Crl was 1.87cm. I also had a scan done at 13 weeks and 1 day, and it was consistent with previous scan and lmp, with crl of 71mm. I am just worried sick that #1 guy could have resulted in this pregnancy, and even if he did do you think I would have had the baby by now? Do you think it is safe to say my husband is the father? I just need your opinion because this has been bothering me the whole time. Your opinion is greatly appreciated

There is no way to be sure without a paternity test. If you don't want to open the can of worms, then just list your husband as the father.

Did you only have sex with #1 once before your last LMP? If so, it is virtually impossible that he would be the father.

However, only a paternity test could prove it without a doubt.

Yes, only that once, I believe it was on the 4th of nov, then my period came on the 17th and all my ultrasounds measure according to my period

Be honest with your husband would be my advise. Regardless of what happens, you have to own it.

Ok, to be honest you need to find out for sure, doctors esp of due date and conception dates are guesses and can be off somewhat.
So what if he is not, and in 4 or 10 years he finds out he is not because of a needed blood test.