Black was over agressive with his pawns here. By move 4, you already developed 2 pieces and castled, and he hasn't even developed a single piece. This should work to your advantage, should you know how to exploit this, and correctly undermine his center.
3... c5 creates light-square weakness in his camp (though it is probably alright still). 4... f5 is too ambitious, and somewhat exposes his king. You should have considered 5. exf5 Bxf5 6. Re1 - you are using the fact that his king is stuck in the middle of the board to your advantage. Already, things like Nxe5 are in the air, you may play Bxg8 if you choose to, or d4, breaking his center pawns. The main idea at this point - open up the center and attack, he is far behind in developement.
Instead you went for 5. d3, which is a bit too tame. You yourself plan on d4 later on, so this practically wastes you a move. This goes to show that accuracy, even in the opening, is meaningful.
6. c3 is the right idea, going for a pawn breakthrough. Otherwise he will have a tremendous space advantage. But 7... b5 was a mistake from him. Unfortunately, you reacted to his threat on your bishop in an automated way - retreat. This is a common error amongst chess players, who "trust" their opponent move, not stopping for a moment checking for other options. You could have played either 8. Bd5, threatening his rook, or Bxg8, and then play 9. dxe5, winning a pawn and completely undermining his center.
He plays 8... a5, which is wrong again, but you did not take advantage of it. 9. a3 serves no purpose - 9... b4 is not really a threat, seems to me like you were reacting to his pawn advance with a pawn advance of your own, defending against his threats that weren't really there, neglecting ideas of attack a bit. His e5 pawn still hangs, and your bishop has a retreat square at c2 if needed (and Bxg8 is still an option).
Finally, with 12. d5, you closed the position for good, and that's when things really start to go downhill. You could still have played 12. dxe5, which wins a pawn and opens up the center, but it seems like that option never crossed your (or your opponent's) mind, something to be aware of in the future.
At this point you just have serious space problems. Your bishops are completely locked in, and your knights also can barely move. You need a game plan here to free yourself, perhaps g3.
19. Bb2 - quite a bad move. The bishop is useless here, completely blocked by your own pawns, and no longer influencing the c1-h6 diagonal. It is clear that you are unsure of what to do here, and just wait for him to build his threats against you. The action is on the king side, and the game may open up there. You may consider Kh1, opening up the g file perhaps, and contesting it with your rooks.
21. Qe2 was probably an oversight which cost you the h3 pawn (though at that point things are getting quite dangerous already). And after 22. Qd2 he correctly played 22... g4, after which things turn from bad to disastrous. Frankly, I don't think white can salvage his game from here. After 24... Qxh4 it looks like black will mate. He had a few ways to win, but fortunately for you he blundered with 27... Qh3+, giving you hope to hold.
Then, he made another mistake with 29... h4, since you could win that pawn (and you did). After doubling the rooks on the h file, you're still worse, but can probably hold the position. Your problem is that your bishops are completely stuck. You should probably strive to place them on more active squares, such as d1 and d2, and simply aim for a draw.
As you probably know, 40. Rg7 was most likely a losing mistake, though it is easy to fall for that in such an uncomfortable position, and in a live game even more. There's no need to analyse further, it is over here.
So, the most important thing I believe you should learn from this experience is:
1) If an opponent plays so agressively with his pawns like that again, completely neglecting development, look for ways to strike at the center and go after his king.
2) Don't be afraid of your opponent's agression and ambitious play, and don't respond to non existing threats. Don't copy his moves just because, look for his own weaknesses, combine a plan, counter-attack.
my bishops were terrible and shouldnt have traded knights for bishops because it was so closed please look at it