The drive to promiscuity

http://news.bbc.co.uk/1/hi/health/8055296.stm
This is a news story about how brain anatomy correlates with sociability. The idea that sociability is an innate characteristic is not proven, since the brain could have grown this way during development due to environmental influences. Nonetheless it's as interesting a thought that someone might have a set drive for sociability during adulthood which doesn't really change.

What I find more interesting than this, though, is the implication that these various drives might correlate with each other, such that people who crave chocolate, sex or other drugs also crave social contact. I've encountered suggestions that people substitute one of these things for another: magazines are full of articles in which people mention chocolate binges that happen as a result of being dumped, for example. I'd never encountered a neurological basis for this before though.

We also have cravings for attachment and romance, as explained here:
http://www.ted.com/index.php/talks/helen_fisher_tells_us_why_we_love_cheat.html
Apart from the fun bits, such as 'we were made to love more than one person', I wonder if all these cravings really can substitute for each other. Can the 'satisfaction' neurons reach maximal activity just from one or two of these (such as sex and chocolate) or do we need romance, sex, attachment, chocolate and social contact?
Either way, I'm not sure that marriage is a good solution. Helen Fisher thinks that we naturally want more than just the satisfaction of one drive that marriage gives us. If one drive, satisfied enough, can satisfy us entirely, why marry at all? Why not smoke weed all day, or eat chocolate, or have a busy social life? On the other hand, if it can satisfy us, why do so many marriages fail?
It seems much more likely that some amount of substitution is possible, but that we really want all the cravings to be satisfied separately.
In this case marriage seems to fight against human satisfaction by specifically denying us the chance to satisfy lust, romance and attachment all at once. Once again it seems a less than optimal solution. Any long-term arrangement that satisfies our desire for attachment does us harm if it also forbids us from satisfying our intrinsic desire for romance or our relatively short-term lusts; people who are attached to each other should accept that what is now called cheating is a perfectly normal and acceptable human trait. We might also notice that this research gives a decent explanation for extreme variabilities in sex drive. If someone wants more sex than someone else, he's not necessarily more base and sinful, just as the other person is not necessarily more prudish.

Of course, we knew this already. It does bring us on to the complicating factor of religion. Religion is a powerful tool for convincing people that things are wrong when they're actually beneficial. Religious people tend to be far less tolerant of drug use (of any sort), promiscuity, satisfaction of urges in general and especially of lust. It does seem strange that God would have made us to be naturally unhappy if we follow His teachings. Of course, much of these teachings are not necessarily God's, but are part of church doctrine instead. Either way, we have cause to doubt organised religion.