Am I crazy or is someone entering the house?

[BaroutC]

A few years ago I found out that my husband had cheated. We separated. He stayed in the marital home and I was the one who left because he didn't want us to separate.
Since returning there have been a handful of times I have felt like someone might be entering the property when there's nobody there.
The first time I noticed it was when we came in from an afternoon out and it was like the furniture had been moved. I couldn't say what had actually been moved but the gap between certain items had narrowed as I walked through.
There were a couple of other times when I wasn't sure but it felt like things had moved. There was one time that I know that something had definately been moved.
Another time our adult DC commented on a strange chemical smell in the house as we entered. I could smell it too but DH couldn't.
It's only ever happened if we have been out during daytime, never evening.
For someone to be entering they would not only need a key but they would need to know that neither of us were in. They would also need to know if our adult DC was staying with us as he comes and goes.
I thought maybe someone could potentially track one of us via a phone, but surely not three separate phones.
I can't see that it would be possible for someone to know when all of us are out.
I'm sure I'm not going mad because I get the feeling only occasionally, not all the time, and there was one time I can say 100% something had moved.
any ideas welcome because I cannot work it out nor why a person would want to enter the house.

Get front and back cameras.

A very spooky movie called I See You is about that, it’s very good. Just don’t watch it alone 😱. Plot twists and turns too.

Yes, get cameras, op, and I’d hide them. The problem is, though, what if there are already hidden cams in your house (and that’s how they know you’re all gone or at home) and so they’ll see you hiding your cams 😳

@Aplume When was a sofa mentioned?

Very interesting and terrifying possibility, Op!

That's what the original story was about wasn't it? Gaslight, I mean.

Explain to me why changing the locks wasn’t considered earlier?

Exactly. The bolt is on the outside of ours too. Plus it takes times to get back up again, pull the ladder up etc amd you could never know exactly when people would return to the house. Amd having to be really quiet all.the rime. I'm a bit sceptical it csn be done for Amy period of time

My xh has accused me several times of accessing my house that he lives in, because he claims things have moved. I have never, ever been in without his knowledge, he is just hugely suspicious and paranoid, could you be like this following his betrayal?

Agree

This happened in our house. A delinquent teenage neighbour was entering our house via the attic. It was only my stepdad living there as my mum had recently died and my sister and I were both living at our boyfriends’ houses. My stepdad would ring me, asking if I’d been back to the house to get things as it seemed like things had moved or gone missing. One day, he said it looked as if there was an imprint on his bed where somebody had sat down on it (probably to rifle through drawers). We finally realised after I’d moved back in and my uni laptop went missing. By then, my stepdad knew who it was but had no proof. The police were called and were helpful and went and searched next door. Found so many of our items in his bedroom, including tools which he’d stripped the copper out of, old phones and dvds players which were worth nothing, all my mum’s rings etc. The error had been taking something that I actually noticed would be missing where as all the other items were hidden in drawers etc. My stepdad thinks he also took a wallet with about £700 cash in it and that he didn’t just lose it when he was drunk…

So you are worried that a person or persons might be going into the house when nobody is at home but you don't know how they are doing that, how they know nobody is at home, and why they might be doing that?
How would you know someone wasn't at home? You could visibly observe them like a neighbour. You could track their phone. You could have some sort of surveillance in the house which you can see remotely.
You're right, OP, it would be nigh impossible to track three separate phones. Even if it was someone your DH had allowed into the house while you were separated, how on earth would they be able to track your phone as well as his? How would they be able to track your adult child's phone?
Could it be a family member who knows where all three of you are going to be because you've maybe had a conversation about it? eg 'we are all going out for the day at the weekend', that sort of thing?
As for why, I can't think of anything apart from the person might have MH issues, like the link a previous poster provided.

Don’t want to worry you OP

https://history.denverlibrary.org/news/denver/tale-denver-spider-man

OK, what if this is actually your DH's doing? Like a previous poster says, could he be gaslighting. Or if not gaslighting, what other reason would he have for letting someone go into the house when you're not there?
I think this is much more likely than an unknown person. It's obviously risky going into someone's house when you think they are out. The homeowner might return home earlier than expected.
Inside job?

Google the Omnivore Trials if you don’t want to sleep tonight.

Some men are just fucking gross scum 🤮

Where do you get 3 adult kids from?

OP said 3 separate phones - her, DH and one adult DC.

Thank you for all the suggestions. It has given me a broader perspective.
There has been some misunderstanding which is entirely down to me as my opening post wasn't clear.
It is just me and my husband who live in the house, with our adult son coming and going, so he could be in the house at any time.
Yes DH and I separated after I found out about him cheating but his cheating had stopped by the time I found out so I am not sure that it would have been the affair partner coming into the house. The reason I mentioned this in my OP was because all the years before separation I never thought any things had been moved in the house.
Yes I had considered whether the betrayal had caused paranoia which was mainly why I hadn't changed the locks. I thought it probably was my mind playing tricks on me and it would be silly to suggest changing the locks to him.
I have never discussed these things with my son. I have mentioned about things possibly moving to my husband, but he didn't seem concerned (which also led me to think that I was imagining it).
The events were far apart - six months or so. So it was enough time for me to sort of forget about it. The hypervigilance would decrease over time to the point that I never thought about it. The event where I knew categorically that some thing had been moved then changed my perception. I knew I wasn't imagining that. I then started to question how someone would know the house would be empty.
The last event happened in the last week. It panicked me a little which was why I posted. I saw something of mine had been moved upstairs but I thought it couldn't have because I had been in all day. Then I realised that the previous day we had been out, similar circumstances, same day of the week to the very first event.
I wasn't asking for advice about how to catch them. I was throwing out the question basically wtf is going on.

is there already someone in your house?

You can easily find out if someone is in your house when you're away by 'papering' doors and windows to see if they are opened when you are away.

Like this - you take a stamp-sized scrap of paper, like a corner of a newspaper page, and fold it up loosely so it's springy.

Then you wedge it between the door or window and the frame, on the side that the door or window opens towards so it's hidden by the frame.

The paper is then disturbed and falls out when the door opens. It can't be replaced in the same spot even if the intruder finds it because they won't know where it was.

This will work with any door or window. You'll know for sure if you have a visitor and how they're getting in, and which rooms they are entering.

You can also paper cupboards and drawers, even fridges, to find out what's being touched.

I learned this in jobs where light surveillance was required.

🧟‍♀️🧟‍♀️🧟‍♀️

I know this is an oldie but.. @BaroutC did you find out what happened?

Oh, my god.