Ironically I was going to address "ignorance is bliss" too expecting you would say this, but I decided to leave it out thinking you would get the point, but maybe I should have went all the way to begin with lol
Ignorance is only bliss when said ignorance is reflected in your reality, when it doesn't there's nothing blissful about it, again it would just be you being ignorant
You wouldn't describe the years that another man was fucking your wife as "blissful"
Rich people who live in a bubble and have never experienced poverty, they have blissful ignorance, because the reality they believe in is also the reality that they experience
Women in modern times have blissful ignorance (with respect to the dating world) because the believe bullshit like "you just have to be a nice person" and that is reflected in their reality because that's really all they had to do to get a date
These groups can be ignorant because reality conforms to their ignorant beliefs, that's truly what blissful ignorance is, if reality was not conforming to your beliefs then it wasn't blissful, you were just unaware how fucked you were
Again, you wouldn't describe the years that another man was fucking your wife as "blissful"
You not knowing doesn't make those years any less fucked up, when you figure out you will still feel the weight of all those years of betrayal, and even if you don't, you'd still be fucked.
If someone is stealing your money and you don't know, you are still "losing money", something of value is being stolen from you, you are being cheated out of something that costs you time and money (your woman in the other case), its a detriment to you whether you can perceive it or not