Think he used going to get food to cheat

So today my fiance left and said he was going to get food....the place is China cafeteria so food is already made and it only takes 15-20 minutes to get there....but it took him a whole hour and 45 minutes to get back when he comes in he immediately goes in the shower and brushes his teeth....seems a little strange to me because u already did these things this morning.....when I ask why did it take so long he claims they had to make his food but food is already done at a buffet...lol men...don't really have proof but soon as I find out on leaving...he has no right sleeping with someone when I'm 30 weeks pregnant he could bring anything back this other girl could be carrying....