I am 29 weeks pregnant as of Tuesday and my Due Date is March 18th. My first day of my last menstrual period was June 11th and the doctor said I ovulated on the 25th of that month. My boyfriend and I are long distance I visited him from June 18th to the 23rd we slept together almost everyday of that trip but when I returned home I slept with someone else on the 29th. I think that would make it my boyfriends child because we had intercourse during my fertal time and near ovulation. But is it more possible that it's the second guy on the 29th?

I also had an ultrasound on Monday and the baby's nose looks large like the second guy. Am I paranoid about the photo? I heard that her nose could be smooshed or that the photos are meant to look larger but I also heard they are very accurate. Please help

Since gestational dating is an inexact science, a DNA test after the baby is born will be required to determine paternity.

LOL, nose looks like, from a ultrasound, yes, that is about as paranoid as it comes. Next even if the baby looks like him when born, guess what, it means nothing. I have 5 boys, if I lined them up and ask you to pick which one looks most like me. 9 out of 10 people will pick the one son who I adopted. So the one son, who is not mine looks more like me.

Looks mean almost nothing, so forget that silly idea before it goes anywhere.

Next, there is no way to know, until the child is born. The dates of sex is too close together.
So a DNA test after birth is the way you will do this.

As to your "fertile time" time of ovulation, how do you know? Online charts are not correct. They are estimates, guesses. So unless you are really tracking ovulation though temp. or other medical testing, you have no idea when you were actually ovulating that month.