I'm only a couple of stones stronger than you, so take this with a grain of salt

8 leaves some aji, but hardly any in real terms. K4 is certainly more normal, though, and it's nice to have L3 to aim at.
10 and 11 seem normal to me.
I don't agree that it's natural to follow up with tengen. Q14 seems normal. Tengen would be an ubermoyo strategy, but black's moyo side has some annoying holes in. Q14 is more restrained. FWIW, Q14 is the move that appears in my database at this point.
15: This move is the first one that doesn't seem natural. Your reason for playing here seems to center around not stopping C3 working, but it isn't obvious to me that this is a good reason. If you played C6, it isn't obvious that white could play to prevent C3 without giving black time to run in good shape. But playing this, you run whilst attacking a light stone (D10), and white still has time to fix his weakness. I'm not saying your move is wrong, but I think you're too worried about keeping C3 alive.
Instead of invading, maybe you could play on the outside of his shape instead? I don't know if maybe H5/H4 or siilar would be a good strategy, but it seems reasonable to seek to push white low whilst making thickness to make a large centre moyo.
21: By this point, it isn't obvious that your invasion has been successful. Your stones are pushing white into the centre, and have no real eyespace. It would be nicer to be ahead of white in the pushing battle.
44: And by this point, your pushing has made white uite strong in the centre. I don't think you can attack this group very well, especially since white has the G13 area to aim at. You're probably doing fine in real terms, but I don't really like the result of C8.
46: A curious move, but I'm not strong enough to say white didn't have a good plan in mind. I thought E3 would be good enough, then white can push down in the K6 area to settle his groups whilst having territory.
White makes what seem to be bad moves to attempt to connect (eventually black can potentially live in the bottom left corner).
I looked at the rest of the game, and thought some moves were dubious, but I'm not strong enough to say that they actually are. It seemed to proceed as might be expected...white uses his strength to kick at your territory.
I think your choice of invasion was non-obvious, and that you didn't really know what you were trying to achieve with it. It didn't obviously fit with the moyo direction of play that you had chosen earlier.