What if?

Lan Zhan and Wei Ying were happily married, Wei Ying was content despite the things he wished he could fix.
Wei Ying was given quite the shock when he wakes up in the past, in HIS 15 year old body not Mo Xuanyu's body.

Aka the au where Wei Ying goes into the past but something is different this time around and Wei Ying doesn't realize until he's being done throughly in the Library Pavillion.

(Basically Wei Ying goes to the past of a different universe where the chapter incense burner is the reality, but because Wei Ying is from the future it goes well.)