Relative Vacations at Our Home

My husband and I have a niece who moved to Colorado a few years ago. She and her boyfriend wanted to come back to our town for a vacation. She is my husband’s niece who contacted him to see if they could stay with us. He said sure. What that entails is we have house guests for 10+ days who sit around our house, eat our food, use our car/gas, watch inappropriate shows (we have small children around often) and do some things that are legal in Colorado but not in our state. My husband is working most of the time and I’m at home with them. I’m at my wits end but my husband said “they’re family” we should entertain them and let them do what they want because they are on vacation. I’m just so pissed! I didn’t invite them here. I think 10+ days is excessive to stay with someone and not offer help of any kind whether doing the dishes or supplying gas in the car they are using. Help! Sample model below, not sure if it’s correct. Give me some ideas so I can survive the rest of this trip.

C – Niece vacationing at our home
T – I didn’t invite them
F – Resentful, Unappreciated
A – Escaping the house as much as possible
R – I’m miserable & can’t wait for it to end; fighting with husband