taesan's mother felt constrained and trapped in the relationship because she's no good at commitment so she decided to leave and take taesan with her. they were in love once but his mother doesn't handle feelings very well (something taesan has picked up) and can't stay in one place for too long. taesan's father still loved them both, she lied about that because in part she didn't want taesan running back to him and also because it's easier to handle her own guilt that way. she has umm a lot of issues!! ty for asking i love questions like these <3