Just to verify, your LMP started on April 15?
It could be either.
You had sex with your ex on day 7 of your cycle. You had sex with your boyfriend on day 8+.
It depends upon when exactly you ovulated, normally between days 11 and 16 of your cycle. The problem is that sperm can survive about 5 days.
Nobody can tell you the conception date. For one thing, it isn't instantaneous. It can take several days. No doctor or test can pinpoint that, nor can they pinpoint to the day how old your fetus is, it's all an approximation. Sorry. Doctors base dates on your LMP. Why? Because almost all women know exactly when that was.
Odds favor it being your current boyfriends but there is always a chance.
Unfortunately there is no hard or fast rule as to when you ovulate or when you conceive after having sex. All women are different and it can vary a few days either way - NORMAL.
It does favor your current boyfriend but there is always a chance.
Good luck Brittany.