Our attraction to our mates pheremones has a lot to do with biological compatibility. Our bodies can sense whether we are biologically compatible with our partner which has everything to do with scent.
My ex-boyfriend was a horrible, selfish boyfriend but my God his scent was the most irresistable scent I'd ever smelled, hands down. When I smell him now, I still absoultely love his scent... but it no longer gives me the same comfort it once did.