Narcissistic MIL. Besides being a bonafide narcissist, she is blind (3 yrs). I feel sorry for her.

I am glad to hear you are in counseling.

If your mother-in-law truly has NPD, she will not change, even with psychiatric help.

Keep her at arm's length, if you can.

Vent about her to your psychiatrist as much as possible. 

Also, does she have a golden child? Typically people with NPD have a golden child and they will often pamper and defer to this child and treat them more pleasantly than anyone else.

If there is a golden child sibling, get that sibling involved.

Visit once a week, briefly.

Have a "fine jar". Whoever starts to talk about her has to put a dollar in the jar.

Good that you and hubs are in therapy. I would suggest a session talking about boundaries. There are also books on the subject (Amazon). It would be worth your time to read up on it. You are setting your boundaries to loose due to you feeling sorry for her. But it is to your disadvantage that you don't make room in your lives for yourselves.

Also have a session about guilt. In order to regain some of your life back, you've got to get over the guilt. There are lots of books on that subject too.

There is even a way to remember it "FOG" , Fear, Obligation and Guilt. Another good topic with the therapist.

Can you start by pulling away from her a bit?
(I'm assuming you and hubs are still working.) Can you visit one evening after work and one weekend morning or afternoon? Like JoAnn said, you don't need to be at her beck and call.

Refuse to talk about her at home unless it's an emergency. You are only reinforcing the "hold" she has on you.

Can you hire a part time caregiver to be with her part of the time (with her money, if possible)?

Did she used to belong to a church or club? You could call and have someone from either visit.

Again, maybe she needs more help now and you could transfer to Assisted Living.

You can say, "Gee, Mom, we're so sorry that we can't fulfill everything you need. But we'll look into seeing who can help you." You can acknowledge her needs but you can NOT give into every one of them. Practice roll-playing with hubby. It's difficult at first, but it gets easier the more you do it.

I understand that even in independent living you have a lot on ur plate. But you can get away. Think what life would be if she was living with you. Boundaries is what you need to set. I made Moms doctor appts at my convenience figuring in when Mom was dressed and ate at the facility. When she lived on her own, I set up one day a week for shopping. A white board was on her wall so she wrote down what she needed when she thought about it. I did not jump every time she wanted or needed something. Walgreens was between our homes. If a prescription was ready if it wasn't needed right then, then I picked it up when I went out. Don't let her run your life. Has she had Some kind of therapy concerning her blindness. When she starts getting negative and nasty that is when you say, Mom if you Can't be nice I am leaving. Maybe it's time for an AL.