Your wife DP'ed by your two best friends. You thought she was joking when she agreed to Swinging. You had to confirm that she knew what she was getting into. "Other husbands will be fucking you". She said, "I know what swinging is silly".
A year later she really got into being the center of attention of adult play. MFM and MFMM were becoming more common.
She got a little flirty at a superbowl you had at your house with 2 of your buddies you invited. You dared her to "get to know them better".
She gave you a look, then started undressing. You grabbed the camera. When things got heated, one of your friends asked her, "Can you take both"?
All she said, "Let's try".
Before you knew it, your wife had 2 dicks cumming deep in her pussy and you got the evidence.