I am still moving this week (closing today) so haven't been playing, but did sneak over for an hour last night. When is the optimal time to get out of this hand?

BB is a horrible passive calling station that will call down with a high and has dumped two racks calling off chips since I sat down 45 minutes prior.
MP is a semiloose to loose aggressive but not a maniac. This was literally his first hand (you don't have to post at this room) and he is still unracking chips from the 8-16 game which just broke. (My read is because I have played with him before). He likes to play a lot of pots and can be aggressive with draws as well as made hands.

Live $4/8 with 1/2 kill game.
I get dealt in MP1
I raise preflop, MP2 coldcalls, everyone folds to BB who calls.

Flop (3 handed, $26)

I bet, MP2 raises, BB coldcalls the 2 bets, I threebet, MP2 caps at 4 bets, BB calls, I call.

Turn: I check, MP2 calls, BB calls, I call.

River: I check, MP2 bets, BB call, I agonized internally and called.

Part of me says I obviously should have got away from this hand at some point, but part of me says that I know BB was such an awful player he easily called with a hand like QJ, and I felt there was SOME chance that MP2 had a spade or straight draw or both.

So what do you do here? Keep in mind the reads because had they been different I would have played much differently.

Online I don't overcall this river,

live though I make the call. So many idiots will play QQ and KK this way not to mention AJ.