I saw on another thread that you mentioned that a "friend" asked you to dinner. What is this about? Just in case one of my possible interpretations is accurate: In your particular sitch, you are still married and cohabitating, presumably sharing a bed. IMHO, flirtations don't seem quite right to me.
IMHO, they seem perfectly right to me. She called the tune; why should he pay the piper? If she's not going to commit or pull the trigger, why should she expect him to (a) commit and (b) not pull the trigger on "friends"?
That's Stay-at-home-Walkaway's problemo, not Thinker's. After all, if she wanted a committed, true-to-her husband, she'd act like a committed, true-to-him wife.
