Tandeming didn't work for us
We had ridden a tandem 12+ years ago and liked it very much; however, I didn't even ride a single then. Got out of the bike thing for years, then finally back again two years ago. I was still slower than hubby, so we bought a high-end whiz-bang tandem last summer to complement our single bikes.
What a disaster! Neither of us liked it, though we could go very fast and beat all our training buddies, even uphill! But hubby didn't like having to call out every little stop, shift change, turn, hill, etc., and I didn't like not being able to see in front of me ONE BIT after being used to riding my own bike. I also didn't like not being able to brake and shift when I wanted to. Girl's gotta have some control, I guess! ;)
We did ride a flat century on the tandem last fall and did very well, then hung it up in our garage where it sat until this summer. We just had no desire to ride it, but were riding our singles (both together and apart) as often as we could. Finally, I put it up on eBay and sold it. It was an experiment that failed.
However, we know many tandeming couples who love it and many don't even desire to ride singles any more. But it is not the answer for all - and we've been married for 19 years so are pretty darn compatible in other ways!
It's an expensive mistake to make since you'll never get all your money back selling it (we lost $1500 even though we had < 300 miles on it), so if you can find one to rent or borrow for more than one ride, it will give you a better idea if taking the plunge will work for you. Tandems aren't cheap, especially good ones that you'll actually want to ride.
Emily