How did you get your wife started playing with others?

A bit of background, we started going together just before our 18th birthdays, I took her cherry when she turned 19, we married at 21 and had our family at 28 and 30, and then she had her tubes tied, all our sex since then has been bare back sex.
I got the itches to start playing and put it to her when we were married 12-13 years, it did not go over to well to start off but after a while she started warming to the idea, I put some opportunities in front of her and she was tempted but did not go through with it. We were 35 and married 15 years and were at a 100% straight party, I was called away to work and knew their was no chance of me returning to the party so I arranged for the wife to get a lift home with a friend of ours Joe, that I knew she was keen on and had been flirting with earlier in the night, as I left I winked at them and told them to have fun.
When I arrived home the next morning the wife greeted me at the door saying she had been a naughty girl last night with Joe, I replied that a bit of a kiss and cuddle never hurt anyone, and she replied “it was more than a kiss and cuddle” I bared up then and there ant took her into the bedroom where we made love as she told me every detail of what happened, we made love for times that day, the bubble had burst.
Monday we got a call from Joe and he asked if it was OK for him to visit with his partner and the wife said yes, when they arrived we were all soon into it the four of us. That opened the door to 10 happy years of swinging, swapping and M F M threesomes, we had a bit of a family problem and stopped playing for a couple of years then got back into it only this time it was mostly M F M threesomes and her being a hot wife with other guys, I love seeing her going with other guys and going silky seconds.
We are now late 60’s and have been married 48 years and are still very happily married and in love, we are retired these days have slowed down a lot on our playing but still have a bit of fun now and then.
Rick181au
PS my wife never touches Holy Water at all, everything she has done she has done stone cold sober.