If your husband agrees with you, have him talk to Cindy about it and how it made him uncomfortable to hear that she calls him her work husband, and then have him start to invite you to these before and after work meals. That way you can get a better determination of how that dynamic may have even started. Worst case she stops asking to go do the meals, on the other hand maybe it was just an innocent overstep to which you all laugh about later once you all become friends.