Should we sell the land that we planned to build our dream home on?

My dad left me about 4.5 acres of land in Washington state. We've been paying taxes on it for the last 15 years, because we had planned to build our dream/retirement home on that land. A land developer has offered us quite a bit of money for my land. My husband wants to sell, and I don't. For what they're offering us, we could easily build dream home somewhere else. But that land has been in my family for at least 2 generations, and it would break my heart to sell. However, the offer from the land developer is very tempting. We wouldn't have to take out a mortgage to build our dream home. What would you do?

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