I have irregular periods 4 months finally got a period oct 3 to oct 9 had sex oct 9 th with boyfriend unprotected had sex 1 time with ex on oct 19 nov 7 pregnancy test negative nov 21 test positive who can be the father

Either man could be the father. With your encounter dates so close together there is no way to even make an educated guess regarding paternity.

You will have to have a DNA test done after the baby is born.