Try to think of her pregnancy as a gift not as a mistake (if you are religious you can think G-d or think of universe or nature if you aren’t).
I’d try to not fixate on the fact that her pregnancy is accidental. So many people are conceived in accident. It’s not unusual or wrong (especially since it’s conceived in marriage and not her mindlessly sleeping around) . Is there any way you can redirect your thinking. Some people might say this kind of thinking of unborn child as a mistake or betrayal sends bad message to the universe.
Would it help to think of it as a human being not as a symbol of something bad and negative. You state her pregnancy had to happen “the way WE planned”. But that’s not hers and your pregnancy, it’s hers and her husband’s. You cannot plan her pregnancy. You could hope for certain outcome. But that’s about it. Something with this line of thinking just isn’t helpful to you.
Is she encouraging this line of thinking? It can’t be good for her pregnancy and unborn child to be viewed in this bad light
I should stop read this thread for my own sanity. Not your fault but this is triggering.