Bettyboo, I have not read all the posts, but here is my take, for what it is worth. I know what you are experiencing, cos I am in the same boat. However, I have been married to my fella for 45 years. When I think back, we have never shared much at all, other than the upbringing of two children, which we did in surprising harmony. But they left the next 15 years ago, and it is very empty.
Like you, we share little. He likes Sci-Fi, I don't. He isn't very sociable, I love company. He is a couch potato, I like to be out and about. He likes an easy life, I like a challenge. We are poles apart, and I almost dread the rest of my life.
But what should we do about it? Our men aren't going to change now, much as we think they should - and indeed, if they were astute men, they would agree, cos if they don't they are in danger of losing their interesting partners. I too have thought about leaving. But I'm not sure I need to. I have developed interests of my own, am treasurer of our local U3A, I got involved with politics, I am a volunteer at a local charity shop. We have separate bedrooms cos I snore (and he doesn't?????) and that suits me, though not what I had planned for my later years. We have two tvs, but most evenings I am on the computer researching my family history as well as chatting with friends and family on Facebook.
It is not at all ideal, and I envy those who share retirement with their partners, but it ain't going to happen for me.
If I leave, I lose my lovely house and garden, I downsize to a bedsit or similar, I will have no=one to change a lightbulb or cut the trees. I don't have a raft of close friends, so I could be quite lonely, even though he is no company, he is at least there.
I would say stick with it, and do your own thing.
I know what it's like re holidays, it is all my doing, and it's like he just tags along. But what is the alternative? Go alone? Very lonely indeed.
I'm not telling you to stay with him, if that seems unbearable, but perhaps with some additions to your own life you can accept that the relationship will never be what you hoped for, and make you own way forward, for yourself.
Meg