I totally agree with @
hopeful. If you can't answer this one easily, you may need to re-evaluate the relationship. As other posters have mentioned, stroke his ego and I'll add, on the intangibles. For example, and this is not ego-stroking, this is true, my SO brings balance to my life. He completely balances me out in areas where I'm lacking. If someone asked him, he'd state that too. He's very supportive and there's a host of other things.
I've always made more than SO and though he had caught up, I moved to another state and make even more now. We both have houses and cars, so I don't need him financially, but it's the intangibles that make the relationship anyway. If all of that stuff were gone, good job, house, car, money, what about him would keep you there? That's rhetorical.
As an aside, I'd be hurt/pissed if my SO couldn't tell me at least one thing that I added to his life.