dating lives: 经常相亲的生活（状态） cut short: 缩短 cut short a blind date： 缩短约会的时间（因为对对方不感兴趣）

'To date' means to get to know someone so that he or she can become your girlfriend/boyfriend, typically on a romantic level. After a date, if the two people involved don't feel a romantic connection, they might become friends, but nothing more. Dating involves spending time with another person so that you can become more familiar with him/her. A person's 'dating life' involves everything that he or she does to meet new people and get to know them better; therefore, if they are well into their dating lives, they are very involved in meeting new people and everything associated with that. Meeting new people is important to them. A blind date is an arrangement between you and a random person. You won't know anything about the other person. It is random so that you don't make any prejudgments about the other person, and so that you can become familiar with the other person by talking to him/her yourself. To cut a blind date short is to leave when you are in the middle of your blind date. 'To cut short' means to end something before it would normally end. For example, after talking to the other person (your date), you realize that you have nothing in common with each other; therefore, you don't want to talk to them anymore, and then you leave. The excerpt you provided is talking about someone who is younger than 30 years old. Therefore, this person does not have much experience with dating, and he or she does not know when they should leave his or her date given that they have nothing in common.