I believe it was a shounen-ai manga but not too sure since it doesn't show much at first.
I recalled a boy started to live with a family of men. They're not old looking. The youngest in the family started to like this new boy and shared food and a bath with him, even had a sleep over. The oldest find it suspicious of the boy. Two of the other boys started to fall in love with the protagonist. One of them kissed him at the school roof top, while the second one like went in shock and punched the other after he witness the protagonist being kissed.
Uhhh, that's all I can remember. Can someone help me out?