Sitting on AKo in middle position...raise 5x BB. 2 people call. Flop is Q92 rainbow. I was first to act and bet about half the pot. They both call. Turn is a 4, everyone checks. River comes a K, not helping a flush draw. I bet half the pot again, and LP goes all in for 20 bucks (we had about equal stacks). LP is average...not too loose, not too tight.

What do you do?