Why is this a problem

I agree with PARCS insomuch as you marry to share your life with someone, and that means doing things together, not everything, but certainly some things.

You need to do some serious thinking Parcs, you say your DH retired 5 years ago and everything has been OK until recently. What has changed?
You have also had stress with your DD, you have them living with you as I understand, and also you feel your DH is "siding" with your DD in the arguments? I have got this from your other thread, but dobn't see how these can be separated.
I find it hard to see how this is a reflection of your actual relationship, but rather that you are fed up to here with the situation at home and maybe you do need to reassess where things are at. Are you still working? Is there no prospect of the young ones finding their own place? There seem to have been some misunderstandings, like over the shared or not shared car and much could be down to a lack of actual communication in the family. You sound as if you cannot make up your mind about what you want. If your DH does not share your interests, go with a friend. If he does sweet nothing in the house and is fit enough to, give him his list of chores or responsibilities. Be clear what you want then act accordingly.
Finally, be careful what you wish for!

Oops sorry, I see they are not living with you but you seem to be very involved in each other's affairs, like the "joint purchase" you refer to and the business of the car insurance. Perhaps you all need to give each other more space, including you and your DH?

Thank you for your comments it does help and really good suggestions
Things have calmed down with DD I am glad to say.

My DH plays bowls competitively summer and winter, he also plays golf one day each week.
I have two close friends - independent of each other, one still works. They know and like each other but we are not a threesome. Nothing definite is arranged but two of us usually meet up at least once as week for coffee, my home her home, coffee shop. We occasionally take a day out to do the shops. We may go to a movie that our DH don't fancy. We may go for a walk. All usually at short notice and on spec.
A few texts and the odd phone call for a chat usually when men would be watching football.
We share concerns and speak honestly.
There are other friends but these two are special, even though they don't socialise with each other.

The men concerned know and like each other but don't socialise unless we have arranged something.

This gives us our own space which. I like to have a few hours in the house on my own now and again.
A couple of days each week me and DH will do something and Sunday is generally family lunch but no pressure if plans are changed.

Space and consideration are important.
We're not perfect..... but we like what we have

Coolgran - sounds like you have got what I hoped for. Very pleased for you and very envious...... My experience is aligned to Parcs' in many ways - so do understand how difficult it is to resign oneself to dashed dreams but as everyone, so far, is healthy, really feel that I shouldn't grumble. Count the blessings etc.

Jomarie I am indeed fortunate but it was not always so.
We have been together for 17 years and married for 10.
Previously I had been married for 22 miserable and lonely years before leaving at age 46. Dashed dreams indeed.

Second time around I made sure I had a good long trial run before agreeing to get married again. Even then it was a big step not lightly taken. We are no way perfect.

And of course, irritations still occur. The oven cleaner is sitting on the kitchen workshop as a reminder to DH that he still hasn't cleaned the oven..... or painted the kitchen...or washed down the exterior window frames etc.
But he will do so eventually.

I think it helps DH that he planned and looked forward to retirement. He also had his sporting interests on the go for many years prior to retirement.

My dearest friend aged 70 has a special other this past 20 years, each with their own home. Another friend aged 76 has had special other this past 10 years.

Age is no barrier for companionship or whatever...My friends were happy to enjoy some 'whatever'

It is sad that you and Parcs might be resigned to living unhappily.
My suggestion to both of you is to forget about any other half being disinterested.
Accept that he will not change...but you can!! Go to the movies, the local theatre. Be upfront and ask a friend to join you. Go out for coffee and cake...a big slice !!! All for yourselves

If necessary, go to the coffee shop on your own and take a book with you and enjoy spoiling yourself. You may strike up a new friendship. Get a new hair style, a new colour, don't even tell him you're going to do it, and don't expect too much of a compliment/reaction. It doesn't matter that you may feel you don't go anywhere special....it's about you recognising that you are special and are going to make the most of life.

Have a manicure, treat yourself. It's wonderful what a confidence builder to your morale and wellbeing a little personal treat can be. If you don't normally wear lipstick then buy a nice soft rose pink to start with. And perhaps a nice (but cheap) pinky floral scarf to drape across your shoulders.
Let him wonder (or not)...... work on the new you. Both of you.

Go for it !!
Even if only at home doing a crossword you can look and feel like a Queen.
ANd never mind Mr not interested.

great advice ,Coolgran! I'm going to take it for me too-thank you!