How difficult would it be to forget your children after a divorce

[Herejustforthekids]

Hello all,
I met my wife 11 years ago, been married 10 and have two children 9 and 8. It was a whirlwind romance and I know very little of her early life other than what she tells me.
My wife is a divorcee and has two children from her first marriage aged 10 and 13 at the time of the divorce. She married young and says her husband cheated on her which caused her marriage to break down. Her husband received custody of the kids and since then she has lost contact with them.
My wife never talks about her two children from her first marriage. She has never mentioned whether she would tell our two kids that they have step siblings too.
I am having trying to understand how a person can cut off their offspring so decisively. There’s a great deal of unprocessed trauma and pain, but shes kept a very tight lid on it.
In the ten years of our marriage she’s not mentioned it at all. When I do broach the subject she just doesn’t seem to be interested in the conversation and just agrees with whatever I suggest.
Do I have the right to tell our kids this when they are older?

Yes.. I suspected that. Men seem to be able to move on relatively quickly. I have been fortunate enough to have been present and involved for much of their life.

OP I guessed it was an Asian country because I grew up with a couple of children whose mothers left them with their dads when their parents got divorced. Their mothers then hardly saw them but when they did came loaded with gifts. I found and even decades later thought this was odd due to the fact all parents lived in the UK. The other people with divorce parents either saw their other parent regularly, like myself, or not at all.

I also went to university with someone who married an older divorcee who left her children with their father abroad. In this case all the men he knew were more upset than the women. I guess as women instinctively thought it was a misogynistic cultural practice particularly as she had no problem with people knowing. Interestingly she took steps to make it difficult to lose the children she then had with him.

‘In this case all the men he knew were more upset than the women.’ While I guess it’s not supposed to be funny, I did find that comment pretty hilarious. It should be the MILs who are upset as they would be the ones doing the grunt work.
‘misogynistic cultural practice particularly as she had no problem with people knowing’ but I wonder if she kept in touch?

OP some people tried to do some digging along the lines of "so you send them birthday presents?" but she refused to answer.

On a more important note it is better to tell your children they have older half-siblings in [insert name of country] while they are as young as possible and just act like it is no big deal. Then if they ask you questions, you can say you don't know. Same for your wife. Then as they learnt about your wife's culture including history and hopefully get fluent in her language, they may understand why she made the choices she did.

I realised I know someone who has adult half-siblings they have never met in a different country for different reasons. I know the reasons why they haven't met them but they don't.