It is always smart in these situations to take a DNA test once the baby is born, just to close the loop. If it sounded like the other guy had a chance to be the dad, I'd suggest you get a DNA test at a lab certified by the courts for determining paternity. But it just doesn't look like there is an issue, so use one of the over-the-counter tests sold at the drugstore. Doing it will put the question entirely to rest (your boyfriend deserves that as well). But don't fret, it just doesn't look like you have anything to worry about.
You prolly just made my whole month! Lol. I want #2 to be the father he is a great guy and has been here for more even when he knew there was a chance it wasn't his!
Was your last period around June 25? Even if not, the conception calculator I use says:
Probable date of ovulation: July 9
Possible dates of conception: July 5 to 13
Due date: April 1 (40 weeks)
It does not sound like Mr. June 21 had much to do with anything.