Before I start, I'm going to say I know what we did was essentially wrong, but please try and understand just how much I adore sex and the fact I'd not not had a mans cock inside me in over a year.
After my husband died, I abstained from sex for a couple of years, even though lots of men made passes at me. It just didn't seem right at the time. Then around fifteen months ago I met a guy who I briefly had a relationship with. The sex was great, but he wanted more and I didn't, so we split.
My daughter Natalie who I have a really close relationship with, lives at home with me now, even though she lived with my mom for a while when I had the brief relationship. We tell each other absolutely everything and because I had her so young, and I've kept myself looking young and fit by my fitness regime, people often confuse us with being sisters.
Eight months ago her boyfriend Jack who Natalie met through me from the gym I work at, moved in with us. He's older than Natalie by two years, being nineteen years old. At first I didn't want him to move in as I thought his presence might disrupt our relationship. And I was right, but in a way I couldn't or didn't fortell.

Natalie was out when Jack got home from work. I'd not long been back myself and had just showered, putting on a bath robe. Jack took a shower and only had a smallish towel to wrap around himself when he'd finished, as he walked past me in the kitchen. As I turned to say something to him, his towel slipped and I saw my daughters boyfriends stunningly muscled body and semi erect cock.
It was one of them moments. He saw me looking, He knew I knew he was attracted to me and his cock began to stiffen. There wasn't any embarrassment between us, and neither was there any words. Jack walked over to me as his cock bounced and untied my bath robe. Opening it wide he put one hand on my left breast and one hand down to my pussy. At the same time, I took a hold of his cock and began to slowly stroke it as we kissed passionately.
When Natalie found us, Jack was just about to put his cock up my asshole from behind, as I was leaning onto the kitchen table. We'd been fucking for about twenty minutes, after I'd spent at least another ten minutes sucking on his wonderful cock and balls. The sex was awsome and I was definitely well into it, when he suggested he fuck my asshole as I was riding his cock on the kitchen floor making myself orgasm on his cock.
Getting up, I dr**ed myself naked over the kitchen table, squashing my breasts and pulled my ass cheeks apart. Jack was just about to enter my rear when we both heard natalie say "Well now I know you can satisfy my mom too". There wasn't the least bit of sarcasm or jealousy in her voice. She didn't go into a rage and start shouting, Natalie stood there and said to Jack "You better finish what you started". Then added "It's not me who's putting the roof over your head". I was totally embarrassed, but Jack obviously wasn't as he drove his cock straight up my asshole. Not wanting to as he began to fuck my ass, I turned to see if natalie was still stood there. Not only was my daughter still stood watching me being fucked by her boyfriend, she'd moved closer into the kitchen as if it was an every day event.
I'd like to say I enjoyed the rest of our sex, but I was too embarrassed and self aware to feel any kind of lust for what Jack was doing to mny asshole, although it did feel good. He came filling me deep inside not long afterwards as they both looked and smiled at each other, something I didn't know until later. Withdrawing his softening cock, Jack grabbed his towel, walked over to Natalie and I watched them kiss as if nothing had happened.

Later that night Natalie came downstairs after they'd been talking for over two hours. It was almost as though she became the parent, as she went onto tell me she was glad Jack and I had had sex. Amongst many other things, she told me they'd spoken about it as she was worried about me not having any kind of sexual relationship (Something we'd spoken about when I had my brief sexual relationship and Natalie had moved out) Like an older person my daughter said "I think you should enjoy Jack just as much as I do, believe me he wants to".
This sharing, this family love, this arrangement, has been taking place now for over five months. Jack and I never have sex when Natalie's around, and I always make sure he wears protection. She knows we've had sex, as I always tell her. And in the last month or so, Natalies been asking me precisely what we get upto, to which I describe to her in detail, when we have our very intimate mother daughter chats.