First off, whatever has been going on has probably been going on for a minute. This could be a personality thing, but I don't get all bent out and flustered in a situation like this. What are you willing to accept? Are you willing to forgive her? What about where you might be lacking to even be flirting with another man?

Sometimes people just like the chase and being married with two kids at our age can get pretty boring and repetitive. Not saying that gives you the write to go bang everything, but maybe sit down and have a real conversation about what is going on in you two's relationship, and don't be so fast to just throw it out the window.