One man, out of assumably four or five others, who serves one or more needs for a girl, but holds no official boyfriend status. Mostly due to the fact that the cumulative needs fulfilled by the others comprise what the total package, official boyfriend would.
A Temporary Boyfriend pursues this usually attractive girl in bliss of the presence of the others in her life. He will likely never reach official boyfriend status because the girl views him as a tool.
A temporary boyfriend, aka TB, is usually referred to as and associated by a number.
Norry: Did you have fun with TB#1 last night?
Diana: Actually, I went out with TB#3, I prefer partying with him because he's a big baller. TB#1 has been really needy lately and is pissed that I won't hook up with him.
Norry: Sounds like it's time that you start taking applications to replace him.
Diana: I was out with TB#2 last night when TB#1 and #5 showed up at the same bar!