I think the real question that should be adressed here is: Is there a difference between lust, love and desire? Are they interdependent or entirely independent emotions? Is love a human fabrication that we choose to believe?
Perhaps humans need to gain some emotional intelligence and confidence with their emotions and take things as they come. If emotions are over analysed and over assessed or constantly questioned we associate the emotion with uncertainty and unclarity whilst this really isn't necessary - we eventually become addicted to the fear of these emotions and see little of the rest of the emotional spectrum.
I personally think lust plays an extremely important role in any relationship, and that if honesty, care, trust and dependence are present too love will follow in the form of self confidence and comfort with the partner and eventually a need for the other - one other than lust. Love isn't like a lightbulb, it can't be turned on or off and nor does it suddenly burn out or get replaced - its about commitment, endurance, experience, faith and trust.