Only your wife has the answer to your questions. I would work to be "curious" rather than judge and jury before you have any information; just tell her what you found and ask her what's going on? It is not about you, it is about her? She may enjoy flirting and be excited by "danger" but here she is, married to you which she knows is comfortable and safe (a good thing) so, for her, it is like watching a horror movie/riding a roller coaster, etc.? It's exciting but does not really mean anything. She cannot very well tell you and get your "approval" or it is not exciting anymore.

It sounds like it could just be a poor choice on her part, not thinking things through to how, if you find out, the "excitement" could be a bit more painful than she anticipated. Try to keep an open mind and see if she is just acting in an immature, careless manner for "fun" or if she is unhappy with the relationship with you (and why). But it is not about you! It is about her and her thoughts, feelings, opinions and perceptions. Her perception that you are "boring" or whatever, does not make it so. Her decision to act in this way is not what I would call mature or very sensitive on the part of a mate? So, don't let her throw stones that connect with you. It is all about her. Tell her you are hurt by her actions (if you are) and, if she was merely bored, would have liked her to share that with you and let you work on that with her? There are better and worse ways to respond to difficult situations within a relationship than going off on one's own like she has. But it could just be "her" and how she likes/dreams of excitement (think sexual fantasies) and you may just want to laugh with her at it and figure out something along the lines of the Pina Colada song?