Jess has a "boyfriend with benefits", but it's not turning out exactly like she'd hoped. So who does she turn to? Why Nick, of course.
You can read some spoilers for episode 3 of New Girl's season 2, "Fluffer":
"Jess can't figure out what's wrong when it doesn't seem to be happening between her and her boyfriend with benefits. In the meantime, she gets emotional encouragement from a more than willing Nick."