
I'm reading this again from the beginning, and now I'm 100% sure that Taesung's mom was in love with Haebom's mom, but because the last one loved Haebom's dad, she gave up and tried to live a "normal" life (get married with a man, have a kid...).
And that would finally explain why Taesung's mom abandoned him for seven years and why she loves Haebom so much... BECAUSE HE IS THE SON OF THE GIRL SHE LOVED.
I wasn't expecting this to be SO CUTE!!!!