My boyfriend used to be a beast in bed.. Now he comes in less than 2 minutes

When I first started dating my boyfriend he was great in bed he could go for so long and please me. From things I've asked him I know he used to be great with all the other girls he was with before me but now for some reason he can't please me he finishes in less than 2 minutes and hasn't made me cum in almost a year he's a great boyfriend and I love him but it's getting to the point where it's having an effect in our relationship he always feels really bad and apologizes and I try to be patient and tell him it's ok but sometimes the frustration gets to me and I can't be nice to him. He goes down on me he plays with my clit and we do other stuff but he just doesn't please me anymore I always think about the fact that with other girls he was great but with me he can't do anything 😐 Is there anything we can do that'll make him last longer? Am I selfish or mean for getting mad at him? Should I let this affect our relationship?