Respecting private space

do you have to stay with him ?

No YANBU.

Remind him that since having separate rooms, the understanding has always been that you wont go into one another's without an invitation.

No, YANBU

You seem to have grown apart and fell out of love with each other. Its a sad situation to live like that and not enjoy each others company.
The document your husband lost could have been very important to him and he didn't know where it had gone? It sounds like he panicked and looked everywhere including the places it wouldn't be. I have often lost sight of things or absentmindedly put them somewhere and my partner goes out of his way to help me find them again.

Looks like you have become roommates

How must do you trust your husband?
This goes beyond invading your personal space

Have a lock put on your door if you can't trust him to respect your privacy. This seems like a sad situation in a marriage.

Much, not must

Why bother staying together?

I don't think you are being unreasonable Nanagem but it seems like slightly odd behaviour from your husband quite out of the blue. Were you happy with the status quo before these incidents, if so I think you need to talk to him about his concerns. If not then maybe you need to think about moving on from this relationship.

Is marriage counseling a possibility?

You say, "but my husband, always been difficult, he’s always needed company, never happy on his own and over the years has become very controlling. I have, until he retired, always loved his company, and I think I just over looked his controlling manner."

this goes beyond having look for documents in your space, does it not? How is he otherwise controlling?

If this is out of the blue behaviour, have you considered he may be getting dementia?

It doesn’t sound like a marriage to me. You need to talk, decide what each of you wants and wether this can be achieved and set some boundaries.

Was your husband perhaps thinking you were keeping secrets before the argument and he was using the excuse of a lost document to search your room?

I wouldn't care if my husband was rummaging around in my room.

Perfectly fine

If you were closer as a couple it probably wouldn’t be an issue that your husband would look for something in your room, I can understand him thinking that you are hiding something.

It sounds like you are in a house share rather than a married couple.

you could probably each find a more compatible flat-mate or lodger.
you don't have to waste any more of your life in an unsatisfactory set-up.

When my marriage was on the verge of breaking up, my ex started going through my stuff and my diary. He was convinced I must be up to something (affair I think). I wasn't. But his searching was his way of trying to find out. It backfired unfortunately, because it was one of the final straws which led to me leaving him. Being unhappy was one thing, being spied on was another.

This is very disrespectful of him. I absolutely would mind if my partner was rummaging through my stuff. I wouldn’t dream of rummaging through his. But, as others suggested, this behaviour could be indicative of dementia so needs keeping an eye on. And maybe a lock on the door.

Have you noticed any other strange behaviour? Do you think it could be the start of dementia?

Yes, what I was thinking about too.

I don't think you are being unreasonable to object to someone going through your things. I lose things often (probable ADD) and am always asking my husband to help me find them, but even though he's been asked for help he would still ask before going through my handbag as he knows that is private, simply because it matters to me.

We all have different concepts of what constitutes personal space, and I realise that a lot of people wouldn't mind their husbands going though a bedside cabinet or a jewellery box, but that's not the point. Those places are your space by custom and practice, and IMO he should respect that.

I don’t think it is unreasonable to ask him to ask first, and to make it clear where it’s ok for him to poke about. It’s about having reasonable boundaries. Could you set new boundaries in a positive way e.g. setting up a shared space and putting important shared stuff in it together?

By the way, I don't agree with some other posters that this sounds like a house share. You have said that you are together all the rest of the time. I just think he finds it hard to recognise boundaries.

Ask yourself if you had lost something would you rummage through his bedroom? There's your answer. I lived a life like that with my ex