1.丈夫或妻子 [zhang4 fu1 he2 qi1 zi5] husband or wife
[例] 我和爱人结婚十年了。[wo3 he2 ai4 ren2 jie2 hun1 shi2 nian2 le5] My husband (or wife) and I have been married for ten years.
2. 指恋爱中男女的一方 [zhi3 lian4 ai4 zhong1 nan2 nv3 de5 yi1 fang1] sweetheart; lover
NOTE: 爱人[ai4 ren2] as husband or wife is only used in Mainland China as a colloquialism. On formal occasions 丈夫 [zhang4 fu1] (husband) and 妻子 [qi1 zi5] (wife) are used instead. Now there is a decreasing tendency 爱人[ai4 ren2] in China. In its place to use 先生 [xian1 sheng1] and 太太 [tai4 tai5] are used to refer to husband and wife, a long established practice in Taiwan, Hong Kong and overseas Chinese communities. For example:
你先生近来忙吗？[ni3 xian1 sheng1 jin4 lai2 mang2 ma5] Is your husband busy these days?
我太太要我下班回家的路上买些菜。[wo3 tai4 tai5 yao4 wo3 xia4 ban1 hui2 jia1 de5 lu4 shang4 mai3 xie1 cai4] My wife wants me to buy some vegetables on my way home.