faking orgasms

Please help, whenever my boyfriend and i have sex he is always really hard but after he cums he isn’t hard anymore and he can’t keep going. And the problem is that he cums really fast even before i finish and i don’t want to make him feel bad so i don’t say anything about it and i usually tell him i came when i didnt. When we have sex it literally lasts less than like 2 minutes. Is there any way to like keep him hard for longer so we can keep going?