He’s an immature loser and a user. If you marry him, he’ll land you in huge debt, as you will be responsible for his debts. You can’t change him. You’ve devoted years of your life to trying. Your opposite views on finances and spending make you seriously incompatible. You say you’ve had your problems but have worked through them. I’ll guess that you worked through them for him and there was no we involved. You really don’t say anything positive about him, so strange that you are willing to sacrifice your future to stay with him. Is it sunk cost fallacy? If he was going to improve, it would have happened by now. Time to MOA and start on the next phase of your life without him. That may be what he wants. This Peter Pan doesn’t want adult responsibilities, which marriage requires. Honestly, you sound more like his frustrated counselor or mother than his near-future wife.