A few quick comments. Up to 31 I feel white's opening is quite good and as a result, the game has already become difficult for black. Tenuki at 32 is sharp. As Chew said, C9 might have been better as it applies more pressure on the lonely stone, but this is very difficult to say - don't forget that black might decide to sacrifice the C7 stone! So at least, I think 32 is not that bad.
38 makes a thin shape. Better to just extend - the aji of black wedging and cutting can easily become nasty for you.
Then black blunders with 43. He cannot defend his lonely stone, the game sequence is too painful for him. Instead he should have played 43 at C13. It's very good that you push through, but instead of 54 you really should give one more atari at E14 (it's not like you'd be erasing aji anyways, your stones are deader than dead already...) and then connect at F11. By playing that, you would build a thick group inside his moyo. That's game over
However, in the game you play a few thin moves: 58 (this is also attaching to a weak group), 62 (why not sacrifice?), 70 (big time aji keshi) and especially 72 (must play at F6, you have too many weaknesses otherwise). This kind of move is not needed when ahead, so you give him good chances to come back, and he takes them...
In short: you have a very good opening already, no need to focus too much on that any more. Now, you should learn that during contact fighting you must build strong groups with:
- Many liberties
- Few cutting points
Then you will not lose this kind of game any more