I recognise what you are saying OP, and feel a lot of PPs haven't experienced it at it's weirdest so won't get it!
I have experienced it a fair bit but it was chronic in my 20s and early 30s. And usually middle aged men. And I wasn't looking, or flirting or remotely interested. Just polite.
At one point it happened about 3 times in one week. It wasn't a case at all of men just chatting about their SOs. They wanted me to KNOW they were taken. And I didn't need to know. It was utterly irrelevant.
The time it happen 3 x in one week, I actually ended up snapping. I was paying at a petrol pump. I literally said, number 3 please, no thanks I don't need a receipt...literally nothing else and the cashier looked angry at me,
practically threw the change at me and said "I HAVE A GIRLFRIEND!"
I was in no way flirty. His behaviour was utterly unhinged. I looked down to see was I accidentally showing cleavage or something that could be seen as a come on as I was just very confused. It was a Tesco pump so lots of other customers in line and they looked as confused as me. Anyway, I snapped "good for you but I was just paying for my petrol, not asking about your personal life!" and stormed out.
Next time it happened the same week, my parents had asked me to let the builders into their house. I'd just met them, showed them where to go, asked them did they want a brew...all men about mid 50s. I brought a plate of biscuits too and one (overweight, 30 years older, not a looker in any way) snapped, "Look love, I'm not being funny but I have a young wife."
I stared him down and said, "I don't understand what a plate of biscuits has to do with your young wife? Why did you feel the need to tell me that? It's just some biscuits, take them or leave them, I don't care either way." and he said "I just didn't want you to get the wrong impression that I was available when I'm not". ???
His workmate looked pretty bemused then later told my Mum I was pretty feisty for a teenager and said they were wondering if I was doing GCSEs or A-Levels...I was 25. So even sicker that a 55 year old thought a 16 year old would be interested in him!
I'd also had the experience of just meeting a man at a hobby or conference or whatever and them going, "Hi, I'm Nick, and you are?" "Hi Nick, I'm Perky, great to meet you. Are you enjoying the event? "Yeah...just to be upfront...I have a wife haha!" A) I wasn't interested, or coming on to them, B) THEY approached ME to start the conversation.
I was always so confused. Men did always shoe horn their relationship status in asap.
It was weird.
I was friends with a guy for a couple of years before we ended up together, and when we first met he did it to me! I wasn't attracted to him at all initially and he wasn't single but we were work colleagues and I said very early on, "Wow, what a cool watch!" (it was a Dr Who Tardis one and very eye catching) and he got very angry at me and said "My GIRLFRIEND got it for me!!!" shook his head and stormed off, looking disgusted. Again, I couldn't understand what I'd done.
A few years later when we were on a date we were stood at a bar and I said to the (again much older) man next to me, "excuse me, can I just reach over and grab a straw please?" and he handed me one and apologetically said "there you go but I am actually taken, love".
I gestured to the 6"5 fella on the other side of me with his arm round my waist and said..."yeah, so am I. I wasn't flirting. I was asking for a straw!" My BF burst out laughing and I asked him why this kept happening to me, reminding him of the watch event and look of disgust he gave me and he said that in all honesty it was guilt on his behalf, I hadn't done anything wrong but he was attracted to me, I was talking to him and he felt that most men take a nice polite woman, being nice and polite as a come on. He said he was tempted and lashed out at me rather than realising it was his issue. I asked him what I should do to stop it happening and he said "don't smile or make eye contact"!!!
As it so happens...having the exact same personality and manners but turning 40, getting fat and not being "pretty" anymore killed it dead. Which suggests it was a shallow looks based thing all along.
I have still noticed though that some men seem to mention their marital status very early and when it's not relevant at all. At Zoom meetings or work related getting to know each other circles;
"Hello I'm Tanya, I'm from the HR Department, some of you will already have met me as part of the recruitment process, so hello again. I've been working for the University for 12 years,
initially in admissions but for the past 3 years I've moved over to onboarding in HR etc etc"
"Thanks, Tanya, yes, I'm Dave. Married! Yes...ummmmm I've been married to my beautiful and better half Elle for the past 8 and a half years now. Yep. Yep so there's that...two kids and everything...erm where was I? Oh yes...I'm the Dean for Teaching and Learning in the Business Faculty and will be your Line Manager, new recruits!"
It's happened too many times for it not to be a thing.
I was once the only woman in a Zoom
breakout with 3 men and they just talked about the fact that they were
married in a congratulatory manner and never got round to the questions until the 60
second warning.
"Hi I'm Tom...I'm married to Helen...for the past 20 years now, together for 23, 4 kids. Helen is a nurse....
"I'm Ben...like Tom I'm married but a newlywed! Esther and I just got married in June...yeah so it's all a bit new haha, I need some tips from you Tom...erm yeah I dunno maybe we should actually talk about erm Sustainable Practice? Erm... instead of my wife? But haha yeah married life is great!"
"If I may chip in, I'm Barry and Ben and Tom I can beat you both - married 37 years to my childhood sweetheart Joanne! So if you need longevity tips haha...well yeah I'd agree marriage is great. My wife always says ...."
blah blah blah
Nothing at all to do with anything we should be discussing, especially in a short time frame when we're expected to feed back. Odd. Sweet. But odd.
"Wife mentionitis". In these cases it's not done for my benefit. Maybe it's more a, "Hey look! Someone married me! Aren't I great?! I HAVE A WIFE!!! I made it!!!" thing? Like they define themselves by it?
It's quite sweet really.
Women ime tend to mention their kids first...and quite early on too.