Apparently, women are happy with their lot earlier in their lives, whereas men have bigger financial goals and tend to be unfulfilled during their 20s, both financially and in their family lives, which makes them miserable.
But by middle age, men have fulfilled their financial and family life goals and have cheered up, whereas women are more likely to be unfulfilled and unhappy.
The authors think a major factor underlying this is the shift in the proportion of men and women in relationships: men are more likely to be single in their 20s, and women are more likely to be alone in middle age.
They admit that this rests on the assumption that being married actually makes people happy, but they point out that if marriage is something you really want (and they found that 90% of both genders did), then being single might get you down.
http://www.newscientist.com/blog/shortsharpscience/2008/07/a...
I wonder how these findings play out for people who are in long-term stable relationships. I'd bet that there isn't a huge gender disparity or "cross-over" for them, since their happiness depends largely on the health of the relationship, and the number of alternatives isn't really relevant.
I get the impression that you didn't enjoy college. Who wants a soulmate so early? Seriously. Only weak and / or disabled people need someone else to look after them at the age of 19.