前任結婚了，你心有不甘，就隨便找個人也結婚，這樣你們就扯平了。可是，這樣就好了嗎？

Spite marriage refers to a marriage motivated primarily by a desire to hurt or get even with someone else. Normally, the marriage will see more people get hurt and no happy ending in sight.
惡意婚姻指為了傷害某人或者與某人扯平而走入的一段婚姻。這種婚姻的結局通常都是，更多人被傷害，沒有人從中得到幸福。

For example:

She soon found out that her spite marriage to Bob was a big mistake. You see, Tom didn't care -- in fact he congratulated them both with the utmost sincerity.
不久，她就發現我跟鮑勃的惡意婚姻是個巨大的錯誤。你看，湯姆根本不在意，他還真誠地向他們倆表示祝賀呢。

（中國日報網英語點津 Helen）