I don’t know what to do

My boyfriend of 8 months recently told me that at the beginning of the relationship he cheated on me. With 4 different girls, while he was drunk. At the beginning of our relationship , about the first 4 months all we did was fight and argue and we weren’t in a healthy relationship, he told me he had abandoned us at the beginning and that’s why he got drunk all the time and did it. He had sex with one of them , kissed 2 others and the 4th girl gave him head. He wants my forgiveness and he wants another chance. The last for months leading up to now ( the point in time that he told me) have been good we’ve been happy and healthy and really good. But he said the guilt was getting to him and he couldn’t live with himself any longer without telling me what he had done at the beginning of the relationship. What do I do?