8. “I’d rather be on my own than spend a future with you.”
“Am I that much of a loser!?” Total disavowal of him will only leave him with a strongly negative impression of himself in future relationships or affect his views on marriage. If you can tell him specifically why you can’t be with him (for example, “You weren’t the right person for the kind of marriage I want”), you can at least minimize the shock to his system.