Sam Wilson is in a fully committed relationship with both Steve and Bucky but will not on his death bed and dying day claim them. He actually goes to see T'Challa and they talk about how ridiculous they are. Sam could be holding hands with Steve and Bucky and look you dead in your eye and tell you he doesn't know them.
Sam’s sister at the cookout: your boyfriends are so nice, Sam!
Sam: I don’t have any boyfriends, but thank you.
Bucky: I love you, Sam
Sam: love you too stranger
Steve calling from the store: baby can you see if we have any milk?
Sam: don’t know how you got my number but we only have a quarter of a gallon left and it expires tomorrow
The officiator of Sam, Steve and Bucky’s wedding: Sam, do you take Steve and Bucky to be your husbands?
Sam: I’ve never met a Stove or a Borky in my life, but I do.