Can we take a break sometimes ?

Last week-end, without even telling (nor asking), my husband put himself in front of the tv and watched one of these documentaries he's fond of. I thought this wasn't fair as I was automatically supposed to watch the kids. On the other hand, he was entitled to this small break. So I was thinking, is there any etiquette of the "me-time on week-ends ?" .
It's tricky for SAHM because when the kids are @ school, we are supposed to be on break until we pick them up...are we ??
Personally, I don't feel I am in break, except for the I-do-it-when-I-feel-it-part but what do I do ? Errands, cleaning the house, balancing check-book(s), doing tax returns (one a year), preparing the next vacations (twice a year), taking care of an 4-person-family laundry (million times a week !!), doing the grocery shopping, taking dentist/hairdressers appointments, dropping off books at the library, etc...
Anyway, I didn't like the idea of "feeling like I am the nanny" while my husband takes some me-time, on a one-way decision. Why should I be the one in charge when they have their dinner before us (so we can chat together while they read books upstairs) ? Ok, I know exactly what they are supposed to eat and how much but how about sharing with Daddy !! My opinion is that we put too much on our plate, thinking that we are the only one we could do it (better). So I started this week-end :
- on Saturday night, my husband brushed the teeth of Mr Son and tucked the kids in bed while I read a magazine on the couch.
- on Sunday night, he gave them their dinner (that I prepared, of course) while I was ironing a few (of his) shirts.
I know lots of men don't like the idea of having anything to do with the kids that involves feeding, brushing, cleaning and eating but why should we be the only ones ? When can we take a break from house chores and taking care of the kids ? So I started this pattern, sharing chores or switching once in the week-end...It's great !! I LOVE IT !!
How do you take a break during your week-end ?