What does Elyot mean when he claims that he and Amanda were too in love for their relationship to last?

Elyot and Amanda suffered greatly because of their respective jealousies and frequent urge to disagree and bicker. They both believe that the only reason they became so hateful toward each other was because they loved each other too much and would grow jealous of any perceived threat. As it is, neither of them can speak of their ex's current spouse without making a sarcastic remark, even years after their divorce.