[Mitke]

* grunch *

Weak - postflop.

As BTN didn't cap preflop he doesn't have AA or KK or AK diamonds - most of the time. Although you stated BTN is moderately aggressive, I assume that means he's not as aggressive as promoted here. So we cannot totally overrule him having one of those hands, they're just not very likely.

He might have a FD + one overcard but that is usually the best draw he can have on you. Then there is the limp + cold-caller MP2 = overlay you can and should exploit.

The flop is relatively uncoordinated bar the FD but we cannot overrule MP2 limping after one limper with a hand like 54s or 43s.

We probably have a huge edge on the flop, have a very good redraw (for FH and Q-high flush) if villains should hit a flush on turn. Just jam the flop for value and protection.

Lead on the flop is good, not raising is bad. The BTN most likely either has a smaller pocket pair than you or is raising for a free card. You might get the to cap if he thinks you might be semibluffing AK-AJ of diamons or similar and decides to protect 99-JJ.

The turn brings more draws and you still don't raise? I might actually lead the turn in hope of either trapping him for 1BB between us and the BTN's possible raise or getting him to fold a 6-4 out hand like 65, 54, 64, 53, A6, A5, A3 in fear a raise behind.

The turn being checked through would be a disaster: we'd lose value and give a free card to the many possible draws there. At least you should have c-raised the turn when given the chance.

River is a relatively blank card. As MP2 looks like he's been drawing all the way I'd be more inclined to choose a line that extracts 2BB from the BTN, doesn't risk the river being checked around. I'd bet/call. MP2 might even call in between but we cannot 3-bet if BTN raises in fear of weirdly played AA/KK or JJ.