Texting an old boyfriend...

I recently looked at my wife's cell phone and I noticed some texts between her and a friend of hers, who happens to be a boyfriend from back in high school.

Let me tell you, these texts seemed to get pretty steamy. I mean, he was asking her how she'd feel about being handcuffed and taken advantage of, and she was reciprocating.

She even went so far as to tell him she should have married him.

When I confronted her, she said that it was no big deal, and neither of them meant anything by it. I told her that, even though I know they hadn't "done" anything, I still felt cheated on. And I pointed out the specific text about marrying him, and she said she was just blowing of steam because of some fertility issues we're having, and that the problem is on my end.

She basically told me that she would just stop being friends with this guy, but I personally think that's the coward's way out. Yes, it would put an end to the texts (I think), but I think part of her punishment for this behavior is to be forced to have the uncomfortable conversation with him. At this point, I know for a fact she hasn't said anything.

Am I way off base here? Should I let this go, or should I be pushing my point of view? Is this really not a big deal?