Male orgasm

Does anyone else has this problem? So my bf masturbated a lot like twice a day before we got together and he did while we were together but when we had sex he wouldn’t cum and I think it’s because he masturbate too much, so now he doesn’t masturbate at all, he’ll cum every now and then during sex but not every time, is it because I’m bad or is it something wrong with his insides? Because I can’t take him not finishing anymore, he can go on and on for hours if he could and still wouldn’t finish and the only time he could cum is if he masturbated and it would be 10 minutes and then he’d be done I don’t get it 😞 don’t get me wrong I love him so much and he loves me but it’s hard to get him to finish