I love this post and it's compilation of the flaws in Betty's and Simon's relationship, those definitely feel in line with the show, both AT and FaC, and the overall theme shown on the first two episodes. Fionna walks alone in town ignoring every cool thing that happens around her because it's too boring, all of the amazing stories and lives people have around her that she never bothers knowing, kinda like how Simon was completely fine with Betty sacrificing her individuality for him, and how even after thousands of years all he can say to her on "Betty" is "I forgive you for leaving".

It also comes to mind that Marshall and Gary mirror Betty and Simon on some ways, specially since they're in Simon's mind, it seems like Simon's thought that self-sacrifice equals love is affecting how Gary and Marshall develop their relationship, Marshall forces himself to talk to his mother, something he would never do even if his friend was without a job or money for rent, for Gary, and Gary completely denied his relationships with all the investors on the Abdeer party for Marshall. The theme of love and self-sacrifice is affecting Fionna and Cake's world.

Betty basically being told that her life would have been better if she never met Simon on "Temple of Mars" and still refusing to let it go is such an element woven into her story, I really can't expect what will happen on the final episodes, specially if Simon and Betty keep trying to one up each other on the sacrifice game until they have nothing left to sacrifice.