four years of closeness和sharing at...which为并列结构,共同组成时间状语从句
she ripped your heart out是主句.
at the end of which的which是代指前面的four yeas of closeness
这句话的大概意思是：四年的亲密,她却在最后把你的心伤透了.那which代指的内容包括sharing at the end of 吗？为什么跨过sharing……直接指代four years……了呢？不包括把sharing at the end of which单独看的话，share算作动词，at the end of which是介宾短语表时间本来这个句子想说four years of closeness and sharing at the end of four years of closeness...但是英语很忌讳重复，所以用which指代。好的谢谢~