Giving my partner $500…?

My partner says he needs $500 to get his truck paid off from the dealership. I’m hesitant because I don’t routinely give out that much money. I’m worried he won’t pay me back because I never ask him for much money and when I do it’s just like $50 or $100 maybe. So idk if I totally feel comfortable with doing it but am I wrong for feeling that way? I offered like $209 or $300 so I’m not cleaned out for the next couple weeks.

I’m just not sure we aren’t even married and stuff. This is why I dislike having a job that makes a lot people look at you like you have enough to support them when they need stuff like this. Maybe I’m being too stingey with my money…? I just worry I won’t get paid back and it’s a lot to give away at once ;( any advice…?