I believe you should have tried to keep the bishop pair. 2 Bs vs B+N was a lot better for you than for him; so maybe you could have avoided the black bishop exchange.
Moreover.. after move 41.b4, you had a decent position but you screwed it up with kd7? (no offense). You had no real need to run for his passed pawns, since they can't get pass your bishop without some moves. You had a nice pawn wall in the kingside that you should have pushed. 40. ....; f4 was a good alternative. by your move 39...a5, it even looked like you were preparing that push but somehow forgot about it.
sorry for not adding specific lines, but I'm kinda sleepy and would probably post wrong ones.
cheers
We both made mistakes...but I was pretty excited when I took his rook and evened the game. Then...I slipped. What could I have done to save my endgame?