Your question reminded me of a trip I took to the Caribbean. Stay with me now. . . there is a link! I went to a restaurant that was serving a buffet. While the entire buffet was all you could eat, they gave each patron a dessert coupon for only one dessert per customer.
Condoms are like that dessert buffet--only one ejaculation per condom! It's very important that you throw the condom away after each time he ejaculates. The condom isn't made to contain an ocean of sperm!
As for bathing between encounters, here's what I'm thinking. If he tries to put a new condom on his penis and his penis is very wet from semen as well as his own lubrication, it is possible that he might not get a tight enough fit. If he doesn't want to bathe between encounters, it would be good for him to at least wipe himself off before putting on another condom.
He also needs to make sure that he puts the condom on correctly, so that he rolls it out completely and makes sure that the condom touches his body and that the condom's reservoir tip protrudes beyond the tip of his penis. If the reservoir tip is tight against the tip of his penis, the condom could rupture when he ejaculates. He also needs to hold the base of the condom when he withdraws from you after ejaculating, so that the semen doesn't spill inside you.
Sounds like you're having a great time with this guy. Enjoy your gift.