Im not sure of your definition of tough love, but with my husband... he has thanked me for helping him get proper medical care for his addiction. I didn't use tough love IMO but I encouraged him to entering rehab where he got the help he needed; did a lot of the legwork to pick out a few I thought would work best for him. he didn't want to go exactly (so maybe I used tough love?) I pushed it with the help of his brother and a doctor.
I did other things which might be considered tough love like suggesting he move out when he was using and didn't want to stop. He hasn't thanked me for that, and there is no reason he should. In our case, moving out didn't help him.. he got worse and used more drugs.. At the time I was angry, I didn't want to live with his behaviors and I thought odds were he would see from this he needed to stop.. I didn't know much about addiction at that time or I wouldn't have made that choice. I have actually apologized to him.
For the most part, his being healthy again is like a living thanks.. seeing him with our son, having him back with us, the way he was before the addiction took him over is all I ever wanted.