Most of us have been here. Not in this specific place, but in this particular situation. It doesn't matter who you are, or your walk in life. If you are married, these things will happen, and you are powerless to stop them.
Your wife is being overly friendly. Problem is... it's not with you. You see her blatantly flirting. Coming on to some tall and handsome man. Acting as if she isn't married. Pretending she doesn't know you. Acting as if you don't exist.
She keeps playing with her hair. Her eyes are sultry. Her smile inviting, as she repeatedly touches the opening of her blouse... nonchalantly guiding his gaze down to her breasts. Her instincts control her. Her ego wants him. Her every move demands his attention.
This isn't her fault. She cannot help it. She finds him quite attractive. She didn't decide to do this. In fact she doesn't even know she is flirting. It's a force of nature. Her primal instinct to procreate has taken control, leaving her powerless to do anything else.
This isn't the first time you've seen her innocently flirting. It won't be the last. You say you aren't jealous, that there is nothing to this. Yet you feel betrayed. Hate wells up inside you and your primal instinct wants to challenge him to a fight.