40/80 JJJ. Can I fold? Please?

[piggity]

Good 40/80 game at the Borg.

I've been playing rock-tight & straightforwardly postflop. The villain here has pulled an all-nighter and has to be woken up to look at his cards every other hand, but otherwise plays well.

I open-raise JJ from UTG+1, folded to the villain who wakes up and 3-bets from LP. Folded to me and I call.

Flop is AJ8, two diamonds. I checkraise, and he calls.

Turn is a blank. I bet, he raises, I 3-bet, he 4-bets.

Can I fold now or do I have to call down?

All comments appreciated.