I'm having difficulty discerning went use the imparfait vs the passé composé.

Question

To me "I felt the nicotine withdrawal" was in the past with a definite end, so I used the passé composé. What reason is used to put it in the imparfait? Then alternately, "Fortunately, my wife never smoked" seemed like a habitual thing, so I used the imparfait. Why is that one in the passé composé?

Answer

This is a topic that takes a while to wrap your head around. It is difficult to argue each and every case but there are some general rules that ought to cover 90% of the cases. I believe there are several exercises on kwiziq dedicated to that question.

One quick check is to see if you could use an English construction that carries a similar temporal feeling:

Je ressentais le sévrage à la nicotine. -- I used to feel (or: was feeling) nicotine withdrawal.J'ai ressenti le sévrage à la nicotine. -- I felt nicotine withdrawal.

The first sentence states a general state of being that something that went on over a longer period of time without a specific beginning or end. In the second example, using passé composé, it is a one time thing in the past.

Answer

sevrage, pas sévrage.   de sevrer par exemple.