Marriage is a compromise. If both of you don’t agree on buying now I don’t see why you should. A compromise is having both of you agree that you do indeed want to buy, but you buy when it makes sense. Your wife should accept the compromise of having the plan to buy in X amount of years and not be childish about having it right now. (By the way, this is coming from a woman.)
If you must buy now, I don’t agree with the logic of buying the condo if you’re going to buy the house a couple of years later anyway. You’ll lose money on the condo; I think that’s obvious. You won’t make money on the condo if you rent it and will probably be cash negative on it. What makes you think you’ll still qualify to buy the house at that point? Even if you qualify, will it be comfortable being responsible for both properties especially if the condo is vacant? If you’re planning on children, will your wife continue to work? Are you basing all of these financial decisions on a two-income family with no children?