Already I can see the chain reaction, the chemical precursors that signal the onset of emotion, designed specifically to overwhelm logic, and reason.
I used to propound on this subject years before Leykis got in on the act. Love is a bio/chemical process that has evolved to stimulate reproduction. It lasts for about the time required to produce 1-2 offspring (pre-birth control).
In the good ole' days (that is, the entire history of mankind up till the Pill), teens would have sex, the girl would get pregnant within a few days/weeks, they would get married, she would give birth, recover, then they'd be back at it and produce a second kid. Total elapsed time: 18-24 months.
After the party is over and the sex dries up, the male is left suporting multiple dependents. Nature plays a very mean game - it will do anything to continue life.