I don't think it was ever mentioned,
we only saw them briefly in a memory of his childhood at the beach, apart from that I think we know nothing.
so I would assume that they abandoned him with his dad
In chapter 26 you can see for a brief moment that Euihyun's mother says she can't take it anymore and leaves him with his father, but thats all that mentioned about her!
Oh it was c28. I was just thinking in the future she might comeback and redeem herself? Like get EH away from TJ and promise him a life somewhere else. Lol
Just wanna know if it was ever mentioned EH mum was alive or dead already?