Your MIL has been a total b**ch to you. I wouldn't feel sad about her death, either. But I would feel sad about other people feeling sad. It's okay to feel relief and a sense that it's almost over. You're not bad or wrong for feeling that. You're very caring towards others, and maybe it wouldn't be a good idea to tell your H how relieved you are (if you're feeling that way...I would feel relieved), but don't feel bad for your feelings. Your T will understand what you're going through, and all you have to do is get through this week and see her next week.