He has a baby mama but he wants me

Good day house, please I need your opinion on this. I have been seeing this guy for 6 months now but I didn’t till last month know that he already has a son with another woman although they are not married. The lady stalked me on Facebook and sent me a message begging me to leave her man for her then she sent me a picture of the three of them together on the day of their naming ceremony. I was really sad, I called my boyfriend immediately and he started begging me that it is not what it seems that the child was a trap on him by that girl, he said that he never even dated her that it was a one-night stand that he cannot even remember. He said the girl is a 16-year-old girl in his compound, that the girl has been pushing herself on him for long but he kept pushing her away until one night he came home weak and drunk and the compound gate was locked that he had to call her to get the gate for him. He said that when she came, she took him to his room and put him to sleep and that the only thing he remembers is him waking up beside the girl, that it was almost like he was drugged. He has been begging me since to not listen to her and that if I don’t marry him, he would kill himself and his death would be on my head. He said would I rather have his death on my head than him loving me for eternity. I am really confused, I like him a lot also, I don’t know what to do, please help me.