Why does my mother-in-law make us feel guilty when we leave her?

In my experience, if you're perplexed by someone's behavior, it's almost always good to pose a direct question. Of course, it's important to actually ask a question, rather than make an accusation in the guise of a question. You might ask your mother-in-law how it is for her when you leave her alone, for example, and whether there's anything you can do to make her more comfortable in your absence -- as opposed to saying something like, "Why do you guilt trip us whenever we go out?"

When you say she makes you feel guilty, how does that work exactly? Does she look sad or does she call you selfish and self-centered? She can only make you feel guilty if you're already part way there. If she looks sad, then you'll have to try to accept the fact that she is entitled to her feelings, and give yourself permission to have needs which conflict with hers -- which is true in all relationships.

It's important for you and your partner to have private time together, even if your mother-in-law isn't happy about it. Remember, it will benefit her in the longrun if you and your partner maintain a strong relationship, and if you take steps -- like having regular times out together -- to nurture your relationship; this will also help you both avoid caregiver burnout. If your mother-in-law attacks you, then you need to make it clear to her that this behavior is unacceptable.

What are the consequences of your mother-in-law making you feel guilty? Does it get you to change your plans? I ask because if your mother-in-law has come to believe that she can control you then you may inadvertently be reinforcing the very behaviors you wish to stop.

I'm also wondering about the bigger picture. How was the agreement made to have your mother-in-law move in? Are you and your spouse and/or children all on the same page? You might want to consult with a family therapist for further guidance.

It is possible she is aware of physical weaknesses that she's covering up, and she may be fearful that "something" might happen while you are gone that won't be able to handle? As she gets older she will hear horror stories about friends (or friends of friends) who have fallen, had heart attacks, etc, while they were alone. Maybe you could get her an emergency button pendant for when you are gone..."just in case"? They make some that can be programmed that when the button is pressed it dials any number you want from the house phone, so they don't have monthly monitoring fees. You could present the idea to her as being like a fire extinguishers or smoke alarms -- no one PLANS to use them, but good thing to have around anyhow. The other way to present it might be to say that you would be more comfortable knowing that she has it.
Does she have a life of her own, or has she become dependant on you to be her sole source of social interaction? Especially if you guys all get along well, she could be feeling like the "third friend" - you know, the who gets left out of things when the other two start dating (funny how much we DON'T change as we get older!).

Oh my god....she lives with you and you feel guilty going out for a few hours or even a few days? She needs a gentle but firm reality check...she's very fortunate compared to those of us who live 50 miles away from our "children" or across the country or even on different continents and are unable to uproot ourselves and move closer to our kids. You might not be able to change her thoughts or behaviors but YOU should stop feeling guilty....that's the reason I'm replying to your post!! I'm aware that everything is relative and she's most likely a stubborn, selfish, unrealistic person (my mother, whom I take care of, which, sadly, limits my time with my own kids). So if discussing my reply with her doesn't help her adjust her behavior even a little bit, I hope you will stop feeling guilty and be easy on yourselves. You deserve your own time and lives and she needs to begin to see that her "glass" is more than half full.