Should I stay?

I have been with my boyfriend for 2 1/2 years. I thought everything was going great, we had a baby together he's 6 months, I love him, he loves me?well when I was leave for work after I had our baby boy he told me he had cheated on me and has another baby with some other girl. this baby is only a few weeks older then our son. he told me it was one time thing and he was crying and very sorry that I was the one he wanted to be with. so of course I stayed with him.

this girl I work with knows the other girl that has the baby. I have talk to the this girl I feel like she hash no reason to lie to me. so I believe every word she says about him trying to be with her the last year and a half. I ask him about everything, he tells me that none of it is true, he told me that she is just trying to break us up? but you see I have caught him and that girl in lies. so I don't know who to believe, because it took him a whole year just to tell me he has cheated. I had asked him way before I had our baby if he has done anything else with anyone, he told me NO. he said he would never do that to me because he loves me so much.
I need some good advice for what I should do? because I love him a lot, but I am also very hurt too

Well since I'm only 14 I can only help you so much. First, you love him so trust Him. Evey relationship goes through 5 problems that causes Break up's. Money, Love, Politic's, family, and most common male Ignorance( '_' ). So trust him or this can be bad for your childs life (kinda like mine was ruin by growing up without a dad). But better or worse you love him, and he loves u.