Am I being cruel divorcing wife of 26 years?

I usually advise couples to do all they can to make a marriage work, but in your situation it appears as if your wife's main concern is about finances, even saying you can date as long as there is no divorce. This leads me to think she is not being sincere when saying she is now willing to work on things. Still, at the face of doing the right thing, why not give it another shot at counseling. Maybe if during this time she can truly hear how much pain this marriage has caused you she will then see how much she needs to change. If after doing this and things still do not improve over time, then of course the reasonable thing to do would be to divorce her. For now it seems her only reason to hold on to you is to be able to continue with you helping her out financially and that is no reason to stay married. Good luck to you!