In most cases, buying a home is a consumption decision, not an investment. The exception is if your mortgage and various expenses are less than your rent -- but that is rare, and very likely not true there.
It sounds like you are happy renting but your wife wants to buy a place, so this is an emotional decision, not a financial one. In that case, the answer of how much to spend on a house is "as little as you can that will make your wife happy."