I mean if you have some substantial proof, confront him about it and be honest about your feelings. But, unless you have proof, you can't just accuse him of being gay.

Sometimes men are just a little more sensitive. My husband is not gay, but he has a soft side that comes out sometimes as gay. 

What has he done that has given you this impression?

My ex had actually had sexual relations with a gay guy I knew incredibly well, but once him and I were together he was incredibly mean toward gay population but always had gay men hitting him up on fb it made me really uncomfortable and it eventually ruined us I wasnt OK with it like I thought every time I got mad I told him to go fuck his boyfriends or say things like remember so and so gives better head then me! He told me I was delusional but when ur gay friend can describe ur mans dick to a T you know he's been on it! Wish you luck!!!