Can you always be happy either way?

I need to understand the concept of: you can be happy either way

In many situations of hesitation, this concept is great and makes sense to me. Thinking: either I chose A or B, I can be happy either way so I just have to think about the reasons to choose one or the other and go with the option that I like the reasons the most, is very helpful to me.

But let’s put it to the extreme for the sake of understanding and say a woman is living with a physically abusing husband, can she really be happy either way whether she leaves or stays?

Thank you so much, have a wonderful day!