Wanting a mistress

I'm very successful in my career and family life, but my wife 43 has health problems that limit our sexual relations. So, as I'm well-off financially, I thought I could get a mistress. At 46 and already having 3 children, I just wanted sex no strings attached. I thought I could hire hookers at first, but changed my mind after seeing a politician get busted by police. I didn't want to shame my wife and children in anyway. So, I started to think of some other way that couldn't attract much attention. I was fortunate to be at a factory I owned, the manager was updating the office operations and that meant some staffer would lose their job. But I'd a no job loss policy, which meant they would be kept on and when someone left, they would replace them. It had one benefit; I liked no training required if someone left as there was already someone available to take their place. But the staffers were mostly younger than the usual and even if single and then married they stayed in their jobs. Only except was the oldest a widow of 54 good looking for her age and the office manager. With the improvements it was her job that was surplus. She was easy to talk too, and I found myself checking her out as a lover. I made a decision to ask her about becoming my personal assistant. Not expecting her to become my lover, but she was what I needed in an assistant. She accepted and the next week started as my assistant. After several trips away we were not lover or anything close at the time. Then my wife had a health crisis, and my PA was great help to me during the crisis. I employ servants but none live with us come each day and are gone at night, a nurse visits my wife either every day or every other day depending upon her needs at the time. As my PA needed a new place to live and hadn't found anything at that time, I asked her to live with me and my wife. We'd a spare bedroom, even when the children were home from university. She accepted and when my wife needed extra help, getting the nurse for that extra help wasn't available at the time. So, my PA helped me and that included showering with me and my wife. My wife got worse and was put in hospital for a week and that left me and my PA home alone. I had gotten hard-on while showering her and my wife and she knew I was sexually interested in her. As I was a bit stressed by my wife's condition, she suggested we shower together, and she would destress me. I agreed not knowing what she was going to do, but she massaged me in the shower and masturbated me off when I got an erection. She along slept with that night and became my mistress for want of another word. I was surprised by her joining both me and my wife in our bed after my wife came home. One problem I hadn't foreseen was my wife getting pregnant, due to the sex we all engaged in and that's how I got my fourth child. Her health was better, and she so wanted the child that I didn't try and stop her having her. But after she had her tubes tied, as a precaution. My PA always sleeps with us both and is more with my wife then me.