Both of us played bad?

I played a 5-10 3handed game at pacific poker yesterday. I was pretty new to the game and the player to my left seemed to be an aggressive "semimaniac" but I wasnt very sure since we had only played for about 10 minutes.

I posted SB and he BB. Button folded and I raised with Qs8c.. Too loose?
He called and the flop came Kd8d3d and I bet. He raised me. I called to see the turn card and it was a nice card, Kc.

I bet out again and this time he only called. I am for the moment pretty sure that he just have the K´s and a single diamond in his hand.

River: 4d
Making board: 3d8dKd Kc 4d

I checked and he bet, do I need to pay off ??
I had the feeling that he was a maniac, but as I said before I wasnt very sure.. But I decided to call him not only to have the chance to win the pot but also notice how he played...

Of course, I lost... He held something like 5d9X (no tvery sure) but he had now straightdraws at all. Did I play the hand like a big fish?
Thx /King_J

[Jason Pohl]

Based on what you state, I like your play throughout the hand. It looks like a free card raise on the flop, so your bet on the turn is solid.

You might call on the river, but that all depends on his likelihood to bluff. There are 6 big bets in the pot (minus rake), so you need to win 1 in 7 times to call his river bet. He could have a pair of 3s, 8s, or pocket pair. He cannot have a draw that did not hit, but he might just be completely out of line if he is a maniac, trying to scare you with so many diamonds.

Conclusion...the only questionable part is the river...and it all depends on your read of the opponent.

Good luck,
--Jason