The major difference between being single and being in a new relationship is that you no longer spend most of your time with your buddies. Relationships can cause a major rift between you and your long-term buddies if you are not careful. If you really care about your friends but also want to keep your girlfriend happy there are some ways to balance both in healthy way.
If you want your friends to remain your friends and your new girlfriend to remain your girlfriend you are going to have to learn to respect both separately and manage your time accordingly. There are only so many hours in the week and most of those are devoted to your job, but your primary focus should be your new relationship. If you really care about the girl you are dating you should put her desires first (as long as they are reasonable). That means reserving specific times during the week just for you and her to spend together. These times should be non-negotiable for you, regardless of your friends have going. You should communicate to your friends that this relationship may be new but it is important to you and you want it to work. Setting boundaries with your friends is a good way to make it clear that you are serious.
On the other hand, you should retain loyalty to the men who have stood by you through all your relationships. They don’t deserve to be pushed to the side simply because you have a new woman in your life. Obviously they shouldn’t come before her but you shouldn’t only call them whenever you want to do something. Take time out to give them a call or hang out with them. More than likely they will understand your hot new love interest, but they may have a more difficult time accepting complete snobbery from you. Also consider that it really isn’t healthy to complete dump your friends and spend all your time obsessed with one person. Keeping that level of interest isn’t healthy so don’t start your relationship out that way.
Balancing your new relationship with your buddies may seem like an obstacle, but it can actually be easy if you are reasonable in what you want from your new relationship.