“He turned as I entered the room, and I took him in my arms. With him, I could give vent to the affection I’d held so severely in check with Merrick. I held him to myself and kissed him as men might do with other men when they are alone. I kissed his dark black hair and kissed his eyes, and then I kissed his lips.”—David Talbot, Merrick.
Imagine your OTP/3 as kids growing up all they until they are teenagers. Person A and Person B are both crushing on each other, and person C helps get them together. Bonus: Later A, B & C all slowly end up together, in a happy mutual partnership.