Is he cheating on me?

Well that is definitely not enough of a reason to think that he is cheating on you. Just because he put on deodorant doesn't mean he is seeing another girl. I mean did he even shower? Fix his hair? brush his teeth? Wear unusually nice clothes that he doesn't usually work in? If not then he wasn't going to see another girl. Every guy makes sure that he is clean/has good breath before they go on a date or if they are planning on kissing someone.