Were you intimate with the new guy on a regular basis from the 4th of september? If so, with your new due date of june 5th, he would be the father. If you didn't, then I don't think it's likely that he is the father. However, your original due date of may 22 suggests that you conceived on august 29th. I know that is the same date of the last time you had sex with the one guy. Doctors use ultrasounds to see how large and developed the baby is to determine due dates. Your new due date of june 5th could just mean that your baby is a little bigger than average. But they are usually pretty accurate. You will probably need to have a paternity test done. With that said, both guys should be aware of the situation.