Talk to him and explain what you told us here. Make sure he doesn't misunderstand. If he's mature, he will understand.
Also, you never really know if you can marry someone until you live with them for a year first. They might seem great when you don't live together, but then when you move in together, all these small things start irritating you, and they blow up into bigger things. You can make your own choice, but living together before marriage is a good experience to really get to know someone, and this opportunity should not be missed.
- Will he leave his sweaty socks all over?
- Will he ever clean the bathroom or will you get stuck doing it all the time?
- Will he leave his towel folded on the towel bar, so it cannot dry out, then it gets smelly and moldy?
- Will he fart in bed and flap the sheets?
- Does he snore?
- Does he make weird gargling noises when he brushes his teeth?
- When shaving his face, does leave his shaving "dust" in the sink for you to find?
I have a long time interest in psychology, specializing in relationship dynamics for 30 years.
(Please note, we give the best advice we can based on the information given in a post. For better advice, please include the age of all romantic partners.)