Is "Tough Love" a myth?

I have read so much about the theory of "Tough Love". I would like to hear some real stories about the implementation of tough love that doesn't end up eviscerating the family members that implement it... or maybe I need to hear survival stories of the family members that did implement tough love... how do you do it and let go?

Last night my husband and I sat down with my son and set out the basics of what he needs to do to be able to continue living here after having to leave his University. We are dealing with a boy who turned 20 in November and the rules that applied at 16 don't work anymore. What doesn't work for our family are late hours that keep us up... sleeping in all day and not working... and little respect for our expectations, which, frankly, aren't that stringent. So let's say he chooses not to comply, or lies about his hours, job search, class attendance at his new school, etc. At what point do we say.. hey... this isn't working... move out and good luck. His step- father could do this much more easily than I ever could. How do I do this? What do I do with the stress that has been created as I try to broker the deal that will make us all comfortable? And if I fail to do that, when do I pull the plug? How do I pull the plug? How do I let my kid go?