co·depend·ency
noun/ˌkəʊdɪˈpendənsi/
/ˌkəʊdɪˈpendənsi/
[uncountable] (psychology)- a situation in which two people have a close relationship in which they rely too much on each other emotionally, especially when one person is caring for the other one
（两人在感情等方面的）互为依赖