Fucking my housekeeper

I'm Paul 37 married 3 children and last December my wife and children went to visit her parents for Christmas. My Parents were overseas at the time and I had to finish a project couldn't go with them. I would home alone but we have a housekeeper Joanna 58 widowed and little overweight and lives with us. Joanna is average in looks and body shape for her age, I was watching some porn on my computer and feeling randy and with my wife away I would stay that way. I couldn't go out and pick up some woman or hire one, too much chance of getting caught and ruining my marriage. I kept going thru different sites and ended up on a mature site and I saw young men fucking older women. Most were really old and some I realized were around Joanna's age and that got me thinking of Joanna sexually and I had gotten a hard-on. I turned off my computer and was thinking of go to bed. Just then Joanna came in and asked did I want anything and could she have a word with me about money. I didn't want anything and said what's the problem, her daughter was pregnant and her husband had an accident and they were short of money until he could return to work. She wanted me to lend her some money to her to help them out and she would pay me back as I could take it from her wages. It wasn't a great deal a $1000 and I was about to say okay I'll lend you the money. When Joanna said would do anything I wanted, I was quick to think about fucking her instead of her repaying the money. I'm not backward in anyway and so I asked her would let me fuck her till my wife came home and I would give the money instead of lending it. She was shocked at first, but didn't refuse it straight a good sign. After thinking it over she agreed and we showered together and I fucked twice and after that night I fucked every free moment I got and lost count of how many times I fucked her. On the family's return everything looked like it always had, except Joanna was well and truly fucked. I also got a liking for fucking her and continued to fuck her at every chance I got. My wife is now pregnant again and Joanna doesn't yet know it, but I'll be using her as a replacement when my wife is too pregnant for sex in a few months time.