Years ago people waited until they were married to have sex. Today things have changed however there are some people out there who do decide to wait. Unfortunately those people are often labeled "Prude" or "Conservative." The opposite sex won't give them a chance.
Other people wait until they are in love to have sex and some people have sex anyway. Some people say that you tell each other you love each other after you have sex.
The last part is not true. If you decide weather or not you love someone by sleeping with them than you do not love at all. That is lust not love. Lust is based on sex. Love is when you want to be with that person no matter what and if that person wants to wait a month or so to have sex you will wait for that person because you really want to be with that person.
Sex is important in a relationship but it is not the only factor in a relationship. You need trust, communication and much more. You have to connect emotionally and mentally in a relationship before you could connect sexually. Sex is between two people who love each other and it is at the right time. There is no time limit to when you should have sex or not.
Don't listen to people who say you have to tell each other you love each other after sex. If you are waiting for that person to say it and then have sex than do it. If the person has to wait after sex than that is only what that person is looking for. Sex is supposed to bring two people who love each other closer. Someone who loves you will understand and want to be with you regardless.