My Wife's Idea

I'm Harvey 34 married to Lisa 32, 1+ child another due in November. I'm well off career wise and financially also, last year year Lisa's mother passed away. Her father died in 2019 (stroke) and Lisa only has one sibling Reanna 30 single a quite shy and quiet person by nature. Reanna started living with us after the death of their mother, Lisa told me Reanna wanted to have children. I said great who's the lucky guy, Lisa then said Reanna doesn't have a guy and doesn't date. I was a bit slow and said how does she plan to start a family without a partner. Lisa said I've discussed that with her and we have decided that you be her children's father. I was silence for a moment or two and said stupidly why me. Your the only man Reanna feels comfortable around Lisa replied, I just looked at her and she added Reanna and I have always been really close and I'm willing to share my husband with her. But only if you are okay with doing that she added, I said being very careful, I'll have to think it over. She nodded and that was that for a week, she then asked me again. I decided to put it back on her saying I'll do as you want, only if it's what you really want. She smiled and I thought I'd saved my bacon as they say. That night I got into bed and Lisa came in and she was followed by Reanna and both undressed and joined me in the bed. So I had sex with both of them and that's how its been ever since. Lisa got pregnant almost straight away, Reanna also got pregnant the following month and is due in December. Reanna is very willing sexually, but I've only fucked her once without Lisa in bed with us. Lisa is very happy with our arrangement and refers to Reanna as my second wife. Reanna has changed her surname to mine and wears her late mother's wedding rings. We've just bought a bigger 6 bedroom house and the wider family know I'm the father of Reanna's child and are very supportive of our family arrangement. My father said as long as we're happy that's all that matters.