2 sentences for 对头 (duì​tou)

1. 他们两家是几十年的老对头了。

   tā​men liǎng jiā shì jǐ​shí nián de lǎo duì​tou le.

   The two families have been old rivals for decades.

   Source: Dong Chinese Dictionary

2. 他们两家因为地界问题一直不对头，经常发生争执。

   tā​men liǎng jiā yīn​wèi dì​jiè wèn​tí yī​zhí bù duì​tou, jīng​cháng fā​shēng zhēng​zhí.

   The two families have been at odds over boundary issues for a long time and frequently get into disputes.

   Source: Dong Chinese Dictionary