I don't get it...

Ok so here's some back story. Girl I know started hooking up with this guy. Didn't use protection from the beginning and said she'd abort if she got pregnant. Guy had 5 kids at the time (multiple women) and she had 3 (also multiple guys). Well guess who ended up pregnant and planned to abort. Also discovered he'd already had a kid on the way but supposedly they weren't together anymore. Well he talked her into keeping said baby and he wanted a DNA test when the baby was born. Test came back at 0% his. She still says he is the father and he did something to the test. Don't understand that at all. But baby is 10months old now and she's still sleeping with him even tho she knows he's sleeping around and has gotten chlamydia 3 times now. So I ask if she's protecting herself from getting anything and she says yeah but I think she's saying it to make it sound better. Why in the world would she continue with this guy?! I'm so confused by the whole thing