12: You are looking unbalanced: a bunch of low stones near the lower side and one lone stone slowly getting outnumbered on the upper side. I'd play something like N16. ( I have no clue what joseki is here )
14-25: My overall feeling is that this can't be good for you. You have at most 10 points in your corner, you are almost completely locked in ( ok, you can squirm down the right side, but that is a net loss ) and he has influence facing his high stones over in the upper left.
I'm not sure what the correct play was, but this can't have been it.
26: Might the top side be bigger?
28-38: Nice flow.
40: Locally, he may be too strong for this. You are starting to look thin. I might play H3. ( Make fist, then strike. )
Note that he has to patch M3 sometime.
42: Atari is not the answer to everything.

You are too thin after he answers. Besides, you force him to fill a weak spot of his.
46: Good fighting spirit!
52: G6!!
60: Nice kill. Remind me never to give you a handicap again.
104: Do you really need this? If you count liberties, I think you don't. G7 solves a lot of life issues for you. You still have S12 if he tries to fight.
106: G7 still may be better. You sac the lower left, but gain sente. You are solid everyplace else, so you invade left and top for an easy win.
124: This would have never become an issue if you had played the geta back at move 52. I know it sounds like I'm not addressing your question, but it is far better to work on not getting into ugly situations like this than to work on surviving them.
You bypass multiple opportunities to connect this group, then ask for advice on how to save it once it has become isolated.
144: You are in a liberties race. Lock him in and start killing his liberties. A7 seems to work.
170-174 etc: Count. You are way ahead. Don't complicate. Just keep reducing with K17. Then reduce westward around G14. So what if he gets 35 points in the upper left? You have close to 100 points.
Invasions entail risks, whereas reductions are safer. Invasions may gain more sometimes, but you don't need more. Play safe and stroll to an easy win.