I would do something like this as well. They're your friends. Be open and honest and see what happens. I'd add that you're also inviting their husbands because you want your guests to enjoy themselves.
Sometimes people see a wedding invitation as a summons from royalty. They aren't any more excited about "having to go" than the bride is about a list of her parents friends she "has to invite." Giving someone permission to not attend is often all that's needed - and if you can frame it in such a way so that its for their benefit (in this case "husbands are invited and welcome, but you all might have more fun without them" or "we understand if you can't make it, the reception is such a drive for you" or "we know you have soccer with Megan almost every Saturday, don't feel like you HAVE to come, although we'd love to see you there") you often get what you want.


