Help me convince my wife..... :)

If money is the main hindrance and you want to fly cross country for leisure and not compete in competitions, have you considered some of the early glass ships that are in the 40+:1 range?
There are some LAK 12's and a 101 Pegase A for sale for $15000 or less on Wings and Wheels.
For $18000 and under you could be flying an Open Cirrus, Speed Astir, T.59D Kestrel, etc.
Yes, some of them may have handling quirks and may not be as nice as the more expensive, newer glass ships but there is still plenty of fun to be had in them at a much lower cost.

I was in a similar situation so I purchased an airworthy Nimbus 2 and nice trailer for approximately $8200 (at current exchange rate). While the handling may not be be every one's cup of tea, it's plenty of bang for the buck without breaking the bank or upsetting the wife.
Club rentals and part ownership was not an option since I just don't trust other people with something that my life depends on. I've seen too many hard landings and glider abuse go unreported and not inspected. Then there is the issue of each member wanting the glider at the same time.

Partnerships work for some people but I'd think that option over very carefully if you plan to fly long cross country flights every weekend.