Should I open up to my mother-in-law about impending separation/divorce?

So, the past years with my in-laws has been quite a trip. They didn't like me the first few years & overtime we really got to know each other. My "mil" in particular. I have grown close with her and the past month my husband & I have been having problems. She calls still to see how we are doing & the kids are doing & she doesn't know. It's just really hurtful for me to talk with her & to have to act like everything is okay. I've thought about opening up with her but I'm unsure if that's something my husband is supposed to do or if we should do it together.