He cheated

My boyfriend of 3 years cheated on me. When I found out it hurt so bad to know that he kissed her and they were talking for around one month.( we were fighting all the time and breaking up too but it doesn’t justify him) But now time has pass by and it doesn’t hurt that much it just me makes me mad and I don’t know if I’m stupid for wanting to give him another chance like I still have feelings for him & I wanted a future with him. But I know it’ll be so hard to trust him because now I feel everything he says is a lie. I don’t think that someone who loves someone would cheat so I need opinions or experience from people who has go through that