There are many ways to define dating, based on these definitions, you will understand better how dating works in American culture. - Seeing someone/casual dating = casually dating, you may be also dating others, or not, and the frequency is low (say once every couple of weeks or so, or even once a week but you don't talk much in between). Movie dates or informal group dating. - Dating/casual dating means the two of you are almost dating exclusively but have not really talked about it. You see one another anywhere from 1 to 3 times a week. You have not discussed exclusivity. Exclusive or serious dating means you have discussed being exclusive, meaning, you will not date others. But you're not talking about anything beyond being exclusive. In the old days they called it going steady. Exclusive might lead to something more serious, or not. In my opinion exclusive is merely what it says, you don't date others, but it doesn't necessarily mean that you will have a bigger or permanent commitment. It's still part of the getting to know you, only on a more serious and committed level. If you are exclusive with someone, then it is not acceptable to see someone else and this would be considered cheating. "Going out" would suggest exclusivety. If you are dating more than one person, you should make it clear to them that your relationship is not exclusive.

In the US it's perfectly acceptable for unmarried men and women to date various people. Usually no one dates "many people". Here's my view on the matter. First, the two people go out, "Go out" means "go out on a date." The man usually asks the woman, but nowadays I think young people don't care if the women asks the man. A lot of people just go out on one date and that's it. They aren't interested in learning more about the other person. If they like each other, they continue dating. You can also say they are "seeing each other." For the vast majority of people this still does not mean sex. (But some might be sexually involved also. It's their choice.) While dating (movies, dinners, a sporting activity, etc.) they chat and get to learn about each other. During this time they are free to date other people also. There's probably still no sex. Most people wait until they are more committed to each other before they have sex. If the relationship gets there, they usually stop dating other people. They're "a couple." If this relationship becomes even closer they might move in with each other. And if they feel they have found the perfect partner, they will probably get married. This is just my opinion, and there are certainly a lot of different ways men and women date, but it's not like people date hundreds of people before they find a partner. Some date just a few people before finding a match; others date forever and never get married. Real American life is NOT like Hollywood films in which men and women just jump into bed with each other after knowing each other for 20 minutes. And they don't just have sex with their friends and their friends' friends and the neighbor, and the postal carrier, etc. : )

Cheating is cheating in all cultures :)

There's no such thing as "Western culture". You have got to stop thinking of China versus the West. It's just not as simple as that.

Being in a committed relationship means that you have made a commitment to each other and are planning for the long term. The next step would be engagement. To be engaged means that you have promised your partner that you will marry. This commitment is shown through an engagement ring given to the woman by the man. One more type of relationship that you will hear about in American culture is an open relationship. An open relationship is a committed relationship in which both partners consent to the other partner being free to have emotional and/or physical relationships with others, often within mutually agreed limits. If a couple in an open relationship are married, it can be called an open marriage.