I'm not using this as an excuse but
he's actually gay.
That being said you ARE right. I've been drawing too much moay moay and not enough REALIZSM!
actually, what you have for the body isn't far off what I've seen the male models look like in my drawing class. regardless of gender the muscles will of course look curvy, so the only real problems I see with your drawing is that the hips stand out too much.
perhaps if you want him to look more manly you should change what he's wearing. you're not going to get him to look intimidating or strong with a skin tight shirt telling people to be happy.
gay does not mean he has to be flaming.