I am a big believer that the healthiest marriages start from healthy friendships - simply because that's how my own began. But, it makes sense. Because loving her is not a sacrifice when I understand that what's best for her is best for me as well.
You take her hopes as your own. She takes on yours. If she succeeds, you win. If you're victorious, she celebrates. There's no competition, because there's no separation of spoils (we'll talk about the pitfalls of "separate bank accounts" some other time.)
In Mark 10:8, there's a record of Jesus talking about marriage by using the poetic phrase, "and the two shall become one." I don't think it's just poetry. I think it's a brilliant understanding of the reciprocal, mutual-beneficial awesomeness of a "sacrificial" marriage.