[derrickdirge]

I just think that's a very reductionist outlook.

Humans are complicated. They have a lot of different needs that all have complex relationships with one another. Everyone experiences theses needs to varying degrees. If the needs that aren't adequately satisfied aren't outweighed by those that are, then it's reasonable for a person to start looking elsewhere to satisfy those needs.

If my wife became a huge economic burden and wasn't contributing anything else to the relationship, then after a year or two I'd definitely be thinking I could do better.