I do not have experience with long-term total celibacy. However, in my two stays at monasteries (only 7-10 days each) I had very little difficulty refraining from lust. I had never gone 3 days without relieving my lust, and suddenly 7-10 days with no problem. I think a large part of it has to do with the routine. First, there are very few stimulating sensations and activities... not just sexual, but no computers, no internet, no music, no pretty lights, no dramatic stories, no dirty jokes. Combined with a schedule loaded with physical labor and meditation, all of the keeping busy with not-so-stimulating activity makes celibacy relatively easy. Combine that with exercises to divert the sexual energy and cultivating insight to uproot the deeper causes of lust, and I can see how a monk might resist absolutely, although it would still be a chore (cleaning the sheets, that is).
Sotthī hontu nirantaraṃ - May you forever be well.