Smoking and BM

I've been a smoker for years. Usually only social or when I feel like one. I've never had to go to the bathroom after a smoke. Unlike my husband who rarely smokes but when he does he immediately has to go to the bathroom.

More recently, the majority of the times I smoke it's like I instantly have to use the bathroom and have had very soft stools/diarrhea. It's been like this for s few weeks. Why is this suddenly happening? Is it just a phase or could I have like an infection?