Mother in Law

My mother in Law Pamela 48 widow is a drunk and gets drunk regularly, she lives with me and her daughter Frances 27 since the death of Paul 3 years ago. We're fairly well off and I work for family company and have to travel a great deal, I usually took Frances with me even after our first child was born and now she pregnant with our second has decided to stay home. But suggested I take Pamela along as my P A after my father said I should get one. I wasn't keen on having a P A and Pamela drank too much, Frances said Pamela won't drink much if she is busy. So I agreed to give it a try, but not sure how well it would work. Pamela didn't much if any at first, but at a dinner she had a couple and I was lucky to be able to leave before she got going. Back at our hotel we had the same room and on arrival Pamela checked the bar fridge to see if any alcohol was in it. There wasn't I had asked for it to ne removed on arrival as a precaution. Pamela asked me what did Frances and we do to pass the time and I smiled at her. You fucked to pass the time and she then said either we fucked or I'm going to the bar and get drunk and maybe fucked as well. With that choice I decided to fuck her, it wouldn't be the first time I've fucked her. She joined us drunk after Paul had passed away and we had a threesome and have had sex on and off ever since. Frances was okay with Pamela getting fucked by me as she thought was better than getting picked up in a bar somewhere and god knows what could happen. Next morning on my daily call to Frances she asked how it was going and told her what had happened and she told me to keep her mom safe.