a) Your ultrasound suggests conception on the 14th. It sounds like it was early enough in your pregnancy to be reliable, and not influenced by when your last period was.
b) You are "worried that everything that is going so perfect will end up going wrong." You are going to have a baby, you are the lucky one no matter who the dad is. Go read the Infertility community if you do not believe me. There are thousands of women who would trade places with you in a nano and they would not give a darn who the father is.
You said "I couldn’t have ovulated anytime after the tenth as I never slept with anyone after the 9th." You are worried on the basis that sperm from the first guy could have lasted from the 2nd to the 7th or 8th, but are saying sperm from the second guy on the 8th or 9th could not have lasted past the 10th? How do you figure that? Either all sperm lasts a while or none does.
In other words, did a medical person come up with the due date of September 6, or did the medical person just tell you a number of weeks and you worked out the September 6 part yourself?
Just to clarify, it sounds like you are saying that you were given a due date of September 6 by the doctor from the measurements of the baby in your first ultrasound. Is that right? In other words, the doctor didn't just give you a "weeks" count and you did the figuring, but the doctor gave you the due date? And he or she did it from the first ultrasound?
I couldn’t have ovulated anytime after the tenth as I never slept with anyone after the 9th xx
Mostly online looking at ovulation calculators, and I asked the Sonographer at my scans and she said more than likely I ovulated after the 7th. My boyfriend is very very fertile this will be his fifth baby xx
If your first ultrasound was at 9 weeks, and from the measurements of the embryo they said you were due on September 6, and then again at 12 weeks they confirmed that you are due on September 6, that suggests you conceived later than the estimate of between the 7th and 10th that you mentioned in your post. Where did you get that time frame for ovulation?
I had a internal scan and I was 9 weeks then had my 12 week scan on the 22nd Feb and I was bang on 12 weeks
How did you get your due date, and when?