she may be trying to protect me and the family
No, unfortunately, she's trying to actually hide the entire story from you. I could be wrong, but as the other posters have stated, this whole story doesn't really pass the sniff test.
As another poster also mentioned, your problem is not him, your problem is her. This close to everything you may not feel that way, but she's the one who got into his car, she's the one that waited until they were not able to be visualized on video, she knew exactly what she was doing, and she knew exactly what this was likely going to mean.
My wife was no different, she hung back and waited until everybody else left the shop, she waited until the man who would be her AP locked up, they waited until the parking lot was empty except for their cars. She knew exactly what she was doing, what was going to happen.
I won't tell you to forget about him, that will never happen. But, remember, she did this to your marriage, he is just the tool that she selected, if it wasn't him it would have been someone else. He's not special, just someone who was around and willing.
Most of what a WS says after discovery is a flood of lies, rationalization, blame transferring, gaslighting, and rewriting the marriage.