I could never have imagined this situation

Your husband is placing you in an untenable situation RamblingRose47 seems like you are living to suit his wishes without any consideration for yours. I understand his illness may be making him stressed and unhappy but it seems he doesn't want you to be involved in his UK life.
I too don't understand the financial issues, if he can afford to stay in UK but you can't I would want to be looking at that more closely.
I think you hit the nail on the head when you said we have been living this separated life for three years^. This clearly suits him.

I wonder if what you want matters at all to him Ramblingrose , you mention at length what he wants but no-where is there any indication that your thoughts, wishes or concerns are taken into account at all?

I can appreciate that he does not want 'a fuss' but to not want the support of his wife of many years? And to seemingly, not care about the distress this is causing her?

Maybe its time to sit down, put your cards on the table and tell him what YOU want and not take no for an answer- he seems to have down well enough bull dozing through his wishes- now its time for you maybe?

Rambling rose I am sorry you are getting anxious and worried. It must be very difficult for you. If you are ever left by yourself would you continue to live in France or would you return to the UK? I would be future planning a bit in your situation and thinking what I would want. I hope things improve for you.

Do you have children? If you have, where do they live?

Clearly you have been together a long time, so you knew what your husband was like, this is nothing new.

It must cost an absolute fortune to go backwards and forwards to the UK and pay for what is essential two abodes whilst this is happening.
Perhaps a little revision of the budget might enable you to travel with him, even if he attends these appointments alone.

You say, He doesn’t like any fuss or attention but he's getting a heck of a lot of that already and probably more so if he has a medical background and may be treated almost like a colleague by the doctors.

So he must mean he doesn't want any fuss or attention from you. Another cause for upset when you want to be supportive.

He's not prepared to act as part of a loving, caring couple, just intent on going his own way as if you and your feelings don't matter. At this extremely stressful time for you both, he should have more consideration.

However, I doubt there's much you can do about it RamblingRose4 you won't change him at this late stage.

Actually I can understand him wanting to be alone.If I am ill I often find that I am better off just getting on with it my myself. I know it is horrid for you and you want to support him but perhaps he is just the sort of person who likes to be ill by himself. I think some people , maybe people who are very practical in their outlook, prefer this way of doing things.

How fair is it to live elsewhere for 6 years become that countries registered residents but still use the NHS

I d want to know much more of why the UK is pulling him back so much first his mum where you say he spent months at a time, and now his health, he either doesn’t really want to live in France or he has a reason to want to be in Uk using his private nature as an excuse
He doesn’t want you with him !!
He goes back once or twice a month !!
I m sorry but this sounds very very suspect to me I d want to know much more about his visits which basically have been going on for over three years
As Stella says where does he stay ? Is the hospital he attends in a similar area to his mother’s home
Am I wrong or have you posted about your worries before it sounds very familiar ?

Just a question - where does he stay during these extended visits for his health appointments ? It just seems odd that you can't afford to go with him, but he can afford to go and stay for lengthy periods without you.

If he is a private person, maybe he just wants to deal with this on his own . You say We couldn’t afford for us both to go over so it seems that you couldn't go with him anyway.

I can understand his actions - I've always been very private with my health, and a few years ago I dealt with a cancer situation without telling anyone in my family . Perhaps your husband wants to deal with this heart problem on his own .

From what you say, he sounds like a man who does things in his own way , so you'll have to go along with that. At least you are close, just being in France, so if he did get sick while in the UK you could go over pretty quickly.

Sorry I can't give any suggestions - I think you just have to roll with the flow at the moment.

Just to clarify the situation. DH has a medical background and is very open with me about his health issues. I see the consultants letters and he explains them to me in layman’s terms. But he is a very private person. Whereas other people would like the support of a wife with them at hospital, he says he would hate it. He doesn’t like any fuss or attention.
He goes back once or twice a month. We couldn’t afford for us both to go over and he often ends up with follow up appointments so doesn’t know when he will return.

I assume that you have considered the possibility that he is seeing someone else when he is in the UK?

If that is out of the question, it still seems like he is being secretive about something, but without knowing him it is difficult to suggest what.

Have you asked him why he doesn't want you to come to his appointments? I fully understand people wanting to keep their medical situation private; but is there any reason why he doesn't want you to travel back with him, particularly if he has a wait between appointments? You could have a little break together, and be company for one another.

In your shoes (which I'm not, so it might not work for you) I would tell him that I am concerned about his going away so much, or that I miss him when he's gone, and I would like to come along now and then to visit friends or family in the UK, see what he says, and take it from there.