I often remind him what an amazing, selfless person he is and how much I love him. How do I know if I'm getting through to him though?
That's one of those Do it anyway, things... as in even if you *aren't* getting through right now, still matters you do it / have done it, as care thrown one's way consistently makes the hard mask and numb cave in with time. And if it doesn't, you still did not only your best, but literally the best you could.
Seriously echoing Sweetpea though - if it's taking too much out of you, it's okay to walk away. Your needs matter as much as his. And from the sound of it, you sacrificed daily enough, for years.
You deserve to have the gift you are cherished. Valued. Not exhausted till there's nothing of you left.