Affair on the side

I married at 19 and have 4 children with wife, who after our fourth child went off sex for quite a while (2years). I really like sex and was very lucky to find a willing replacement for my wife. I was 32 at the time my wife 31 and my new sex partner 46 and my wife's aunt younger sister of her mother. Her aunt was divorced and lived across the street and my wife, and her aunt had no secrets from each other. My wife knew it was a problem for us with her not wanting sex at all. Her aunt didn't have a boyfriend or lover at the time and was horny you could say. Her aunt looks like her sister and my wife takes after her mother. A couple pounds extra at most, they came to an agreement where her aunt would provide me with sex till my wife got over her problem as she called it. I wasn't asked, I was more or less told of their agreement and expected to follow their decision. I was a bit shocked at first, but as I said I really like sex. But didn't rush into bed with my aunt-in-law, I thought it wouldn't look good to be too eager. After a bit of talking, I agreed as long as my wife was in the bed with us. At least for the first few times, my wife accepted it and joined us in bed almost every time till she recovered her sex drive. Needless to say, I was very happy with the arrangement and after my wife was willing to join in sex with me and her aunt. We had several threesomes, and I again got her pregnant just before her 34th birthday. Her aunt still hasn't a boyfriend and isn't looking as she prefers our three-way arrangement. It has been Hassle free mostly and we have her over most weekends overnight and sometimes during the week. But as my wife gets closer to having second daughter, her aunt is my primary sex provider.