7yrs a lie!!!

My bf of 7yrs had a child with another woman, if which he denied having any involvement with when I questioned him about her prior. The child is 3yrs old which he recently told me about this yr. I was hurt and felt betrayed especially after he continuously told me he did not want kids. I care for him but there is no trust and at one time I hated him. He wants to make it work I'm on the fence. Do I leave or should I stay???