My daughter and her partner have recently split, but both attended my son's wedding in May, when things between them were strained, but the announcement hadn't been made public, largely because of the wedding. You wouldn't believe the number of people asking them separately and together when they would be getting married, or commenting that 'it'll be your turn next'. It was awkward to say the least.
I also remember an aunt of mine who was known in the family as 'Mad Auntie X'. She was the worst at intrusive and impertinent questions. Once at a funeral she went round all the young family members asking how many O levels they had passed, and having embarrassed them with that one went in for a second round of 'are you courting?' My cousin had just broken off an engagement, and another had failed his O levels at the same time as his twin, who had passed all hers with flying colours. I was newly married at the time, and she asked me when I was planning to have children, and if I'd give up work when I did so. for all she knew I might have been trying unsuccessfully, or have just lost a baby.
There is just no need. People don't ask adults about their sex lives, or how much they earn, and young people have as much right to privacy about their own personal lives.