Suggest Treatment For Lack Of Pleasure During Ejaculation

When having vaginal sex with my partner, he ejaculates but does not feel any pleasure. On rare occasions he feels pleasure, but not usually. I am not sure what is going on and what to do to improve the situation. Here are the details: My partner is 24 and uncircumcised. He feels pleasure while ejaculating through means other than vaginal sex. He says that he masterbaits about twice a week. I am the first and only sexual partner that he has had. We have been having sex for one year now and he says that this problem has occurred for the duration. I am 22 and have had only one sexual partner before him. I have never had child. Also, I think I might be more wet than normal...so maybe there might be a problem of proper friction, but I am not sure. Because he does not feel pleasure, he has a low sex drive. What is going on and what can we do to improve the situation?