She decided to stay for a bit

I share that opinion. We do not know what problems or issues you have besides that you have memory problems. That is not a reason for her to be cruel to you. It sounds like she is leading you on and toying with your emotions. If you do in fact have memory problems, wouldn't it make sense to see a nurologist? I think it would be a normal reaction to this emotional relationship she has with your friend? From what I have read, she doesn't treat you right and blames all the problems in the marriage on you while she comes and goes as she fancies. What she says goes and you do not seem to have a voice in the marriage. She comes back home and you are delighted. Then she leaves the marriage up to a therapist then she tells you as far as she is concerned the marriage is over. Do you not want to have someone that treats you with at least fairness, honesty, kindness, decency, gentleness and love? I would even think that being away from someone who is so callous would be welcome. Maybe something to think about?