Originally Posted by MFCT

One would think she'd be living with her BF and not you. Which indicates he's a person of little means. Probably jobless, probably living with parents or in a really ratty, shitty crackhouse-type place with no privacy. But he also probably has tattoos and drug connections, so she's head over heels.

Her lending him the key was probably a test devised by both of them, to see how much of a pushover you really are. If she gets away with it, she has the green light to be banging him in the privacy of your nice apartment, in your nice bed, whenever you're not home.

After he does his business with her, having the option to take any valuables you have to trade for drugs/pills is just a bonus.