I have seen this with my H as well. He was a smoker when we met. As the R got more serious I talked to him about quitting. I did not nag as he never smoked in the house or anywhere that I was with him. I just wanted him around longer as his Mom and her 9 siblings all died early deaths due to complications from smoking.
When I got pregnant with our first child, H decided to quit. He remained smoke free for 26 years, except for 3 weeks when his mother died.
When he left and moved in with ow, who is a smoker, he immediately took it up again. This time with a vengeance. The kids have reported that he's a chain smoker, as is ow.
When the kids asked why he started smoking again he retorted that it was your mother who made me quit.
I have seen him with a cigarette since and it almost like he is saying see, I can do what I want.
To me it seemed like he was a teenager saying, I'm doing this and you can't stop me.
I don't know if it was him "showing me" that he had washed away any influence I'd had on his life.
Yep, he has certainly shown me by golly. The only thing is that he is destroying himself to do it.