|Liza Minnelli and fiancee Desi Arnaz, Jr.|
Some think it was the age difference. When they got together she was 25 and he was nineteen. The first time they met was when a 9 year old Liza walked in to Desi's bedroom (who was then 3) and announced, "Hi! I'm Liza."
Others think that Liza, spending so much time on the road doing concerts, ruined it. The fact that on one of those concert dates in London she conducted a wild month long affair with Peter Sellers probably didn't help.
The other conventional wisdom is that Desi was madly in love and desperately wanted the marriage but Liza was gun shy.
After finding the above picture, I've developed my own theory. Having to sit through the premiere of 1973's Lost Horizon is enough to kill any relationship!
Why do you think these two crazy kids couldn't make a go of it?
**note to self: you can't put your hand that high up on a 19 year old's thigh with out them getting that far away look.