They're not both going to get everything they want. It's just not going to happen, plain and simple. They can both end up very happy with the home they buy, but only if there is some sort of compromise along the way.

Who ends up compromising what comes down to price range and necessity. Things that are needed can't be given up, and most people can't suddenly qualify for 25K more. It's easier to give up yard space because you still have a yard. It's easier to give up a garage stall because you still have a garage. It's easier to give up upgrades because you can upgrade later. If there isn't an island in the kitchen you might be able to buy one. If there isn't a formal dining room a dining area might suffice.

As long as you don't buy a home to go with your furniture you're on the right track. Nearly every time someone is buying a home to fit the furniture they have, the inevitably pass on a bunch of homes only to decide to get rid of some of the furniture in the end anyways. It's usually because one person loves the furniture a lot more than the other.