As I see it, the most important question is: Do you want to build a boat, or do you want to sail a boat? Building a boat is a HUGE job, (and REALLY expensive), but it would be quite an adventure, and an amazing accomplishment. So if you're itching to build a boat, go for it.
On the other hand, if what you want is to go sailing, then buy a used boat. There are so many great quality, cheap used fiberglass boats out there that building makes no sense at all, unless what you crave is building a boat.
One last point- if you're married, and she's not as excited about building a boat as you are, then you might as well fill out the divorce papers now and get it over with.
Cheers, Steve
PS- Have you considered multihulls?