Whether we like it or not, in the real world it is extremely difficult for two people to be romantically together without developing deep feelings.
It's just human nature when it comes to attraction.
The more the attraction resumes, the more it will probably become an unconditional love over time.
Despite something terrible that we talked about before, the simple truth is that one or the other of the two involved probably would have lived "fairly happy" after the end of a long-term relationship