I find it hard to believe that the OP is so unaware of real life that he is still wondering if it could happen. Of course it happens. Most of us were groomed to think of ourselves as "regular guys" but we also found that "regular guys" can sometimes bond so deeply that sex happens; and we think of it as "doing what comes naturally" and may continue on that path for years before we finally fit into the pattern which our society sets for us.
I have always wanted and needed the companionship of men. Two friends, both married with children as I also am, appear to the world as typical married husbands and fathers. Each of them has had the hots for me as I have had the hots for him for many years. I, and each of them too, am pleased and complimented to know that I am sexually attractive to each of them as they are to me. We have not ever stepped over the line, but I think we would still be friends if that should happen.
I am always aware of those animal urges which find me "stirred" when I am in the presence of a sexually attractive person; and, I am grateful that that most powerful sexual organ, my brain, keeps me on the straight and narrow path.
Let's face it: some of us are more easily stirred than others. I have straight friends with whom I will my brain to look past their fantastic sexual attractiveness.
Our societies have not worked these things out fully, but things are certainly better than they were seventy years ago when I was at the beginning of my very happy journey into the fullness of my sexuality. The persons who shared that journey with me were a diverse lot, but people of normal intelligence and good witll can bridge those differencea.