disagree with nofacegirl in the first chapters while K and MC's relationship is left romantically ambiguous it is confirmed that they had been at the least in love with her for 10 years and they had lived together and K had told them she was a lesbian that never wanted to have kids. For someone you love to suddenly spring on you that they're getting married and having a kid with a man is crazy and heartbreaking and MC had every right to feel betrayed and upset.
Wow I hate the main character, in this they're very selfish towards other people. Like the person, they used to like they got very upset because the person had a kid and got married just be happy for them, instead of being angry that they somehow betrayed you because they like men now and had an kid, people can change and for one the main character should know that, from how they did try to date a boy and it wasn't right for them. ಠ︵ಠ
