I get what you are saying. Except with my husband, it works the other way around. He says he wants a divorce or offers me one when he thinks I actually want one or thinks he can't make me happy, and what he really wants at that time is for me to talk him out of it or make him feel I am ok with everything. It's as if telling me he wants a divorce is his way of pulling ME back to him because he knows I will always try to talk him out of it.
While that may not be the case for all I think it may apply to others that they simply offer a divorce because they don't want to hurt you, not because they really want a divorce. You have to be the judge of your own situation to know what they really want to hear and whether they want a divorce or they just want to feel they can get through whatever they are going through without losing you.