The Back-Up Plan
You're creme brulee when the other person wants Jell-O. Or you're Jell-O when they want creme brulee. What we're saying is, you're around until something better comes along.
Boyfriend and Girlfriend
Wait, what happened? Oh, right. Nothing better came along so you guys are still together. And it works. Most of the time.
That ended horribly and now you're a Taylor Swift song. You're also never, ever, ever getting back together. Well...maybe just for break-up sex.