I am so sorry that you are out of other options than a TKR. It is so stressful waiting and hoping that things will turn around and then such a dull sinking feeling when your waiting is over and its not the outcome that you had hoped for. At least you will be out of pain and back to your normal life in the near future.
I know you are really young for a TKR, but there are others out there who have done it and greatly improved their quality of life. My sister was in her mid-forties when she got her TKRs and now at 61 they are in perfect shape. You should know that she is well over 300 pounds, so if hers are still perfect with the stress she puts on them, yours should last a great deal longer. They're talking 30 years now and the designs are better. Just incidentally, her surgeon was a professor at Johns Hopkins who has since passed away. The difference in pain was so significant that she argued him into moving up the date of her second knee(he wanted her to wait 6 months). You are wise in getting that second opinion in a top quality school, even though it means being patient again!
I know that your surgeon will say it is not a good option, but unless he has a better one that will let you fully live your life and enjoy your family and work without pain, I guess it is the only one. I would expect that for many OSs there is a real sense of failure when they are unable to heal their patients and have to move on to a TKR sooner than the ideal, and that may encourage them to delay the inevitable at the expense of the patient.
For myself, I expect to live to be quite old, most likely over 100, and when I had my PKRs I knew that I would probably have to follow them with TKRs eventually. They are doing great, so hopefully that will be quite a while from now, but I couldn't have continued to have a normal life if I had put them off. Its part of the risk you take in exchange for getting your life back.
Good luck as you go through the next part of the journey.