I have said to friends (younger then I) that sex changes you emotionally. But I never had that type of explination! Not that I completely understand it, but I think I get the gyst.
Here's another idea, avoiding sexual relations inside marriage is also determental to the emotional well being, not to mention the marriage. I've seen this in older couples I know, my parents included. There's a change that seems nearly completely negative! They lose a closeness. OF course it can't always be avoided, but if it can it should. As with all things in marriage, this should be ballanced.