Yunduo's feelings are complex and her question to Xioaen can't be separated from her current dissatisfaction with her life. She loves her children but clearly regrets where she's ended up somewhat. Did she actually know about her feelings for Xiaoen back then or is she searching for a lifeline that wasn't there? She's definitely latched onto her current feelings for Xiaoen as a "what if," though. It's unfortunate.
What's great is you could see the gears turning in her head just from her body language in the previous chapter. The questions she was likely asking herself and the future she was imagining. I think even now, if she could, she'd want Xiaoen to be with her and with her kids.
Obviously that's not in the cards, and realizing that someone else is the one who showed Xiaoen that there's another romantic path--that must have cemented things for her a bit. She thought she'd missed something or that Xiaoen had kept something from her and that, that could explain how her life has ended up this way but in reality there really wasn't an alternative future that she was left out of. That also must hurt to think about.
She's been asking herself "where did it go wrong, and what could have changed it?" She seems to have thought she had an answer and that turned into a dud, quickly.