I can only go by my own experience. I am under the UK retirement age, as is my wife. I retired through injuries. When i arrived in France 3 years ago, my bank manager told me to go to CPAM immiediatly to register and apply for a Carte Vitale. She then started the process for a mutual assurance to compliment the health cover. This cannot be completed until you have the attestation for the Carte Vitale. Unfortunately, i met your dragons sister. I did not realise that she had not registered my visit on the computer, despite her copying all my legal documents, and disability certificate. (Not severe disablilty) After 3 visits, one with a different lady who was very different and tried to help. She was younger, and junior to the dragon sister. I realised that i was actually getting nowhere fast. That none of my visits had been recorded from June 2013 until February 2014, despite them copying all my papers on each occasion. I spoke to my French GP, and to the Marie, and i wrote a 'robust' letter of complaint to CPAM. As a result, i was seen by a senior social worker, (Different department) at which point everything changed. She could do nothing about the non recorded visits, and had to start the process again, but i recieved my Carte Vitale attestation a few weeks later. She all but agreed the staff had lied, but she was in an unenviable position, where she was unable to prove it. My mutual assurance was activated the same week and we have been covered ever since.
As to cost. I make 3 payments of 250 euros a year to CPAM via URSSAF, and 71.38 euros per month Mutual assurance. I consider that to be excellent value for money for two people.
Record every visit you make, and get them to sign it, or prove they have recorded your visit on computer. If they take copies of all your papers, obtain a reciept. I did not, so i cannot prove they had 3 complete copies, and they deny ever having them. Next apply to see a social worker and explain the situation. Back up your story with a letter from your doctor as to your medical condition, and from the Marie, proving your residency. Do not take no for an answer. If you back down they will ignore you. It appears that once they realise other professionals are involved, their attitude changes somewhat. In addition, the social worker arranged for my wife and i, to be registered disabled with the MDPH. We had no idea that she had done this, until we recieved an appointment for assessment. After the assessment, we were registered very quickly. We had no intention of applying for this, but are very grateful.
As a result of CPAM's incompetence, i had to pay a bill for one night in hospital for my wife. The hospital said that as my application was in i was covered. At the time we did not realise that the visits to CPAM had not been recorded. Result, a facture for over 1400 euros. I appealed and fought the facture for 18 months, but without the proof that i had registered with CPAM before the hospital visit, it was a waste of time. On the upside. We have had fantasatic medical treatment ever since. Last year i had several major operations for health problems i did not know i had. My wife had an accident and had both knees replaced. The treatment and after care, have been the best i have ever experienced.
Finally, the fact that your husband is French, just backs up exactly what my neighbours have said. (They are all French), and that is, that foreigners do not get treated any differently. The French go through the same bureaucratic nonsense that we do. The notion that we are treated any differently, is just not true. What does make a difference is not backing down, and trying to learn the language, or using an interpreter until you have at least a woking knowledge. Not needed in your case.
I'm not sure that this information will be of any use to you, but maybe it will serve as a warning to others. I hope everything gets sorted out as soon as possible for both of you.