These are mine:
- Almost everyone gets married, so when you’re in your 20s/30s thinking it will never happen, it probably will. Haven’t seen much infertility but maybe that’s still to come given age.
Actually have quite a few unmarried friends now in their 50s and 60s. Maybe because my profession is one that encourages complete immersion. Also know plenty of co-habiting couples.
Most marriages seem healthy and strong
Have seen quite a few split-ups, but overally probably yes.
- Seen two affairs, both ended marriages with kids
Same here. Though kind of wondering if the affair (which in both cases went on to a relationship) wasn't there to do exactly that thing (and yes, I thought that was a shoddy and cowardly way of doing things, though I knew that both marriages were unhappy and needed to end).
- Mental health is a massive thing in lots of people’s lives - I think there is a lot of responsibility when you have young kids, need to earn etc and that’s often how the stress comes out, hoping this will get better as kids get older etc. Also know a few people our age with serious physical health problems
Certainly see a lot of that. Well, I would, since MH problems are hereditary in my family (long-recorded history going back at least to early 1900s), but also because of my job. Ditto physical health problems. Life is, to some extent, a valley of tears.
- Interestingly with all the Caroline Flack stuff in the papers (not saying she did anything) we have known two cases of wife on husband DV, no husband on wife cases
I've only known male on female- including one case where a lovely young woman was killed by her partner. 
- Re my parents and their circle, health got quite wobbly for a few people around 60 so good to have financial options
Of course it's good to have financial options, but given how many essential jobs in society are either low-paid or precarious or both, it is unrealistic to imagine that that can happen for everybody, unless something is done about how we remunerate people's contributions as a society. I'm in my 50s, fully trained academic with 30 years' teaching experience and decent publication record, still on precarious contracts. My financial option is basically to drop dead at that lectern before I need to start worrying about my pension. And I'm one of the lucky ones: the people doing arguably more necessary work as cleaners and carers far less so.