How does a gal politely let her female best friend (of 15 years) know that her husband is not invited on every outing that we plan? If I say it's a girls' night, she says, "Let me check with my husband"

...and, then we do not anything because he guilt trips her about not being invited... ON A GIRLS' NIGHT. Sigh. It's been 4 years since I have spent a girls' night with my friend without him showing up.

I miss my friend. What do I say?

p.s . The husband is 41 years old and acts incapable of caring for himself.