Finding the win is a cinch in that position - if you've got the time. I simply have to calculate the knight paths, which is about the only tricky part, and then I coordinate my pieces.
*My opponent knows that. It's completely different from a complex situation where one believes they might still be able to win.
This is plain boring, to be frank. I essentially played myself the entire game, and then when my opponent has nothing to lose they hop the knight around or whatever other piece trying to run the clock down.
OK - hoping to help here, but not sure what your beef is (maybe time was low?). You were up a piece, and from move 34 on there were no N moves, but supported the B to move to control the queening square. Anything, even Rf1 to prevent Bf4 would have been enough technique to win. You sac'd the N to get the P to b8, but it wasn't enough.
I'd argue that until you (and me) get to the point where we can consistently win a won game, and not drop pieces unnecessarily, this is exactly the kind of loss that can guide you to what you should be studying - simple forking tactics included.
I'm in the same boat frequently, and it stinks to lose a won game, but hard to fault your opponent here...