Thin line between love & lust...or no line at all?

One of my old, much thought-over, favorite paradoxes...thin line between love or lust...or no line at all? Frankly speaking there was a time...when I believed less in love and was driven by lust....be it due to age, be it due to experience, it was like this....but over time....over newer experiences....we mature...we learn...we learn to learn....and we learn to love...and we love....and be loved....and I think now that there IS a line between love and lust....however....love followed by lust could make the experience very precious, worth-while, but the opposite is possible but not worth it. I mean I believe from my layman's knowledge and observation of animal kingdom and biology that...its possible for a man to draw a line between love and lust...they can fall in love with one woman and sleep around with other women...without loving them ofcourse....they need a PLACE to have sex....the question is whether a man should do that or not? especially when love is already in place with a special woman, and there are issues of ethics and morality...after all...we are humans...so my answer is NO. On the other hand, I think women don't usually separate love and lust, in their eyes, its more interwined..so they need a REASON...to have sex......so my question is...is it wrong to admit that you..as a male.. would be attracted to opposite sex at the first instance, there is nothing wrong in that...only if you know where to draw 'the line'? or should a man alltogether lie and deny this?