Hey Pete, I think you're a good bloke and are very honest for telling us about your domestic situation, but I think your HTFU comment is probably appropriate right now, if the only reason that your life is so "good" is because whenever there's a confrontation you back down to her.
Let's face it, you probably own everything you've got, you work hard, you're not putting your family's finances at risk, all you're doing is taking up a bit more room in your garage with something that you've always wanted, something that will continue to grow in value. If you let her win every argument, then you're not living mate, and as much as I hope reincarnation is real, there's no guarantee that you're gonna get another run at it, so I think you need to make a stand.
Buy it, bring it home, she'll either get over it, or get out of your life. Either way, you've made her understand that while you appreciate her opinion, you're not ruled by it. Cheers, Terry.