Wife texting with ex boyfriend

I found out that my wife has been texting her ex boyfriend from about 13 years ago. Our relationship is just ok at this point in our 10 year marriage. Us having 2 small children and working opposite work schedules has left little time for us. She has been dealing with some anxiety issues and has been seeing a psychiatrist once a week. That I know of she has never cheated on me but about 3 or 4 months after our wedding she made a plan with a friend of hers to go out to a club and meet up with the same ex boyfriend she is texting now. He never showed up apparently because she wrote an email about being mad at him for not showing...which is how I found out about that episode. Well fast forward to now and she started texting him again. The fitst few texts were harmless but when she says "I hope your fiance knows how lucky she is" and later "i think deep down I hope you know how I feel about you"...that really hurt. How do I handle this situation? Do nothing and hope nothing happens? Confront her knowing that she might get upset with me spying on her? I am pretty hurt and I don't know what to do. Any and all advice will be appreciated.

I appreciate what you say about me having to do work on my situation...however how does one approach their wife with this information without being accused of spying. I was thinking of having a no-distraction conversation (kids in bed, no tv/phones) and asking her how she truthfully sees our relationship and if there is anything she wants to talk about because I can see a tangible difference in our relationship and her specifically. Basically give her a chance to be truthful and maybe she might confide in me about texting with her ex? If she doesn't and insists everything is fine then I am afraid I will not be able to hold back my anger and pain from what I found. I hope this doesn't sound silly because there is ZERO evidence that a physical affair has taken place. However when he said in a text "it would be cool to see you again" and her reply was "I work nights at 'Retail store' so it would be awesome for you to stop in and see me"...this makes me nervous that if I don't address the issue now that something could happen.