The problem with some people when they get into a romantic relationship, is that they leave their family and friends behind. They spend all their time with their new love interest and don't go out with their friends as much as they used to or talk to them on the phone as often. It's understandable that they'd want to spend time with their new boyfriend or girlfriend but it should be more of a balancing act where friends aren't thrown away only to be brought back into the picture if the relationship ends.
Unfortunately there are some men and women who attempt to isolate their new love interests from their friends and family. They manipulate the other person making them feel bad if they choose to spend time with other people. People like this can be dangerous as seen on television shows like Dateline, 48 Hours, or 20/20. They're controlling.
If someone doesn't encourage you to have your own life, more than likely you'll find that the relationship will have a terrible ending of either mental duress and/or possibly physical harm. If your friends are concerned about the person you're seeing, more than likely they are correct. You're blind they're not. They have nothing but your best interests in mind. Your new love interests probably doesn't even if he tries to convince you that he does. Very few people have ever regretted spending a lot of time with loyal friends but have regretted investing so much of their lives into bad relationships.
Young people more than likely won't understand or heed to this message, but I sure wish they would because it will make their lives so much more enjoyable and safer.