Definition
This idiom describes someone who is repeatedly in a supporting role, never achieving the main position or recognition in significant situations.
总是做配角，无法当主角
She always dreamed of being the company president, but it seems she will always be a second-in-command, always a bridesmaid, never the bride.
她一直梦想成为公司总裁，但似乎永远是二把手，总是伴娘，从未当过新娘。
In every election, he is always an indispensable part of the campaign team, but never the candidate; he is always a bridesmaid, never the bride.
在每次选举中，他总是竞选团队中不可或缺的一部分，但从未成为候选人；他总是伴娘，从未当过新娘。
She has received multiple Oscar nominations, but has never won, it seems she is always a bridesmaid, never the bride.
她多次获得奥斯卡提名，但从未获奖，似乎她总是伴娘，从未当过新娘。