There are so many red flags here.

Two young children from two different moms

Dating multiple women at once

Not ending things with his other girlfriends BEFORE committing to you and posting the relationship on FB

He couldn't decide between you and the other woman so he asked his friends to help him make a decision?! And the deciding factor was not that he had stronger feelings for you, but that you "made more sense" because you were closer in age. It sounds like he may have had stronger feelings for the other woman, but only turned her down for practical reasons. Personally, I would never date someone who was unsure if they liked me or someone else more, and needed their friends to help them decide. It seems like he still has feelings for the other woman, even if he's decided not to date her.

You guys only met three months ago and have only been dating one week, and there is this much drama already...

It sounds like he has a long history of moving through relationships pretty quickly...