Decide what your husband wants and what he doesn't get: men leave because they feel something is missing, missing, or died in the marriage and they have no idea how to get it back.
(And if the marriage has been in trouble for a while, you probably know all of these things too.)
Often these missing items have a lot more to do with them than with you.
Look, men fall in love and fall in love because their wives make them feel.
