I have been with my DH for 12.5 yrs, living together for 10yrs, married for 6yrs. In my experience, if your relationship cannot survive for periods of time without sex, it will not survive. All relationships have their sexual peaks and troughs. Of course if it is lacking from your marriage you should try to address the issue (or more likely underlying 'issues'), but if sex it the thing to break a relationship 'in and of itself' then that was a pretty crappy relationship to start with.
that's a really good point. right now i guess you could say we're going through a 'trough' but we're still very much in love and very supportive of each other. yes sex is very important for a relationship i think, but i also think the relationship has to be strong without it as well.