When I put your dates into my conception calculator, I get June 5 for the date of conception. This would not completely rule out the guy with whom you had sex on May 29, but it would be pretty close to ruling him out.
It was exactly 2 weeks before my second ultrasound and both time I had gotten that due date from both ultrasound
Would your first ultrasound have been on July 6? If not, when was it?
How did you get your due date, was it from the first ultrasound or the second?
It is obviously less possible for a guy who did not ejaculate to get you pregnant, but it is not impossible. It would help to know the exact date of your first ultrasound.