Question for "second wife's"

[Qwerty323]

Apologies for using the term second wife. It makes me cringe too lol.
But I have a question..
How much do you know about your partners relationship with their first wife?

I'm a "second wife", my partner was in a long term relationship that ended about 6/7 years before we met. They lived together, bought a home together, and had children together.
Recently when I asked a question (in conversation) that linked to when he was in said long term relationship and he gave a very short lacking in detail answer. When I thought about it I realised he's a very closed book regarding that relationship (therefore a fair sized chunk of his life) and I'm wondering is that normal?
Do fellow second wife's know much about their partners life with their "first wife"?

I’m a second wife (husband widowed). I was a bit curious about her and know quite a lot about her but I don’t think it would do me any good to delve into their marriage.

Lots, he offers information rather than me asking, I'm completely open too. We are both still friends with our exes and (not an issue currently but thinking ahead) we will invite them and their dp's to our wedding if we have a proper one. Might be unusual but there's no secrecy, I met his ex early on and she gave me lots of tongue in cheek tips!