You must have had your reasons for splitting up with your ex girlfriend so I'd reflect back on those reasons and don't make a mistake in going back with her (whether it was her fault or you simply fell out of love with her). Since she has a boyfriend there is no way she can know at this point who the father of the baby is and don't fall for it! A Paternity test is needed to see who the real father is and this can only be done after the baby is born. If it is your child then you should be man enough to pay child support and decide if you want to be part of this child's life. It's tough for a child to go through life without a mom or dad and knowing one or the other never wanted them. If you're old enough to impregnate a girl, you're old enough to start acting like a daddy when you have the proof you are the father. If she loved you she'd leave her boyfriend, but the truth is she isn't sure this is his baby or yours. She may have simply fallen out of love with her present boyfriend and was angry at you for the split-up and had a rebound romance. Tell her she's going to have wait to see if that baby is truly yours and then you'll talk. Right now she is still with her boyfriend and let it stay that way.