He found out 8 years later another woman had "his child"...?

Help! I am co confused... I 've been with my man for 10 years now, Im 28 and he's 29 years old. We survived many things, but now I dont know...I gave birth to his son 2 years ago and I was happy until 8 months ago he revealed a big secret. It turns out (while I was pregnant) he 'heard through the streets' that there was this woman claiming he was the father of her child... He's s real sensitive guy when it comes to kids, so long story short, he checked it out. And he told me later b/c he did'nt want to complicate the pregnancy and he was waiting for the right time. He thinks this little girl has his eyes, her name is dynasty, she is 8 years old..Her mom is ghetto from what I hear, and the child thinks another man is her true poppa. I have no idea why this chick is comming with it now, 8 years later.. Anyways Im so upset...I never wanted to be a 'babymomma #2' He's taking a DNA paternity test next week, and Im scared this could be his child...I hate it!!! I wanna leave him but then that makes me a single mom? He said if she was his daughter he would'nt jump into things and slowly build a relationshio but tell her he's her tru dad later, later on when she can understand, maybe at 13 years old... Im praying its not his kid...I love him and hate him now, although the other woman hid it from him for so long I feel she has ruined my life too.What should I do? He says he'll stand up to the plate but not pay child support to the mother, since he never knew. He will only bring the child around 'our family' once in a while....This shatters all dreams I had of being a family with no dark secrets..I feel kinda sorry for the child too since the dad she knew walked out on her a long time ago and she has a lying mother.. Whatever my man wants to do is his business, but should I stay with him?