I think you defined their love perfectly. In Korea, she had no family or friends. She had a mediocre job. Until one day, she pairs up with a rich powerful hot guy and suddenly she moves up in the world. Plus it doesn't help that her purpose of living started to revolve around him.
Now she has status, not a lot but enough for her to be considered important. She has a supportive family that gives her unconditional love. She's satisfied and realizes her previous relationship wasn't healthy.
Precisely~~ She feels nothing now because she was desperate before but now the desparity is gone~ And on his end I think he didn't notice that at first he was desperate and then became obsessed with the fact that she was literally too perfect of a match to let her go.
But I think that he was obsessed with her even when they were in Korea.
As he said, he hated her at first ( let’s not forget that he was basically an hostage in Korean since the saintess didn’t open the portal for him to go back to his dimension and the government tried to tie him up with a guide) I might speculate that even their marriage was something the government proposed.
I think that just like she said, he was always on the edge, they might have been some threats towards him and FL, which is why he was so overbearing about her being out…
Long story short, he was obsessed with her even in Korea, but since all ML in manhwas are allergic to communication, he never discussed with FL who was letting her love for him consume her. So it’s nice that she got to heal and it’s true, she doesn’t need him anymore as she did in Korea, she doesn’t need his validation anymore
Circumstantial love occurs when a situation is unavoidable and another party meets all requirements of the desperate party.
Example: It's an apocalypse and you meet the only other suitable human being that meets most of the requirements to be a romantic partner. As a result "love" blossoms- so to speak, however when you run across a safe haven with more people (thus more options) the desperate party now has the opportunity to solidify the relationship with the current partner or find a new partner.
ML really didn't understand that his situation was dire until he crossed worlds and matched with the only person who could meet his needs. In other words his love was a case of delulu. BECAUSE HOW DO YOU NOT TREAT YOUR WIFE LIKE A HUMAN BEING YOU NUTCASE. HOW DO YOU MARRY SOMEONE AND DONT SHOW THEM AN OUNCE OF LOVE?!?! YOU TREATED HER LIKE A PET YOU DOUCHBAG!!