Perhaps you do not believe in the marriage vows you took to love, honor and cherish, in sickness and in health, for better or for worse, as long as you both shall live. OP apparently did at one time. Something interfered with that after 29 years. She is obviously hurting emotionally and striking out with trying to justify her action by an act of infidelity 15 years ago. At the heart of every divorce question is the question of what happened and why is the party preparing for divorce. The money part is just the finish, just like no lawsuit is about making sure it does not happen to anyone else. It is about money.
Maybe I believe in the vows I took and recognize she may be doing this because all her friends and counselors are telling her to do so, not because she wants to in her heart. As someone who had to live with a spouse who's friends and coworkers told her repeatedly to divorce me, at the same time I was doing everything I could mentally and physically for my family and her, including paying off the house we own, I see that side. In fact, when I became so disabled I could no longer work and my wife had lunch with my sisters, to see if they would take over care of my mother, they not only said to dump my mother, who I have cared for solely for years, one said she should divorce me and go find a husband who could afford to spend lots of money on her. I could go on with with how one took most of my fathers retirement money and left me and my wife to support him also and could only bother to show up at the hospital when he was on his death bed and never came to my home to see him. I suppose it was a last minute gesture to hope they received something if he had any money left.
The point here being this is not a normal 5 or 10 year marriage with a cash out at the end.