What do you think of me waiting to break up with my girlfriend?
Do you want to wait to break up with her so that you can avoid hurting her?
No! I wield Russian coldbloodedness. I'm thinking of keeping contact with her after the breakup.
You are being very deceitful in this scenario - both in prolonging a relationship you want to end, and in hoping to keep in contact afterward. If you want to break up with your girlfriend, you should just do it instead of wasting her time. Also, whether you can keep in contact in the future is up to her just as much as it is up to you.
Everything will be fine once I end this with her.
She's going to be hurt a lot if she finds out that you lead her on only to break up with her later. How would you feel if she did something like this to you? A lot of people would believe that this all sounds very messed up.