Be careful when you fool around you might just fall in love.

Scientists have found that the same part of the brain which is stimulated by lust is also the part of the brain responsible for bonding and love.

In order to map out the location of sexual desire and love, researchers reviewed 20 studies that used fMRI technology. First, they looked at the regions of the brain that lit up when sparked by love. They then compared the findings of all the papers to see what regions were activated when someone felt aroused or amorous.
What they discovered was a bit surprising — love and sexual desire both activate the striatum, showing a continuum from sexual desire to love. Each feeling impacts a different area of the striatum.
Sexual desire activates the ventral striatum, the brain’s reward system. When someone enjoys a great dessert or an orgasm, it’s the ventral striatum that flickers with life. Love sparks activity in the dorsal striatum, which is associated with drug addiction.