Is my boyfriend of 2yrs gay?

Gay Issues and Problems

When i first started dating my current boyfriend and we would go out he would always get calls from his friend, which he calls "brother" because they've known each other for years. Sometimes we would be in his car hanging out and it be like 2am in the morning and the "brother" would be calling my boyfriend non stop. When my boyfriend would answer the call he would get out of the car . My boyfriend use to rent a room with the "brother's" family where my bofriend and him shared a room.About a year later I found out throgh other people that my boyfriend and the "brother" owned a house together, which my boyfriend had never mentioned to me. The "brother" is about 32 years old and has never had a girlfriend or dated girls. Later i met my boyfriends blood brothers and i found out both are gay! My boyfriend and his "brother" do everything together and my boyfriend use to give him rides to work etc. Also once in a while when my boyfriend and i go out on dates for example the movies the "brother" comes along with us, which really bothers me and my boyfriend pays for all of us! I've confronted my boyfriend about his sexuality and his relationship with the "brother", but my boyfriend swears he's not gay and that him and his "brother" are just close. Is my boyfriend gay? Im really confused please give me advice!!!