How to disappoint my girlfriend and be indifferent to me?

It's just the cold war. First of all, you can't be disheartened. If you really love her, you should seize the opportunity without excessive premise. Don't dwell on that kind of thing, you should take it step by step. Since I can still sleep in the same bed with you, it means there is no big problem, but you are really angry with your dishonesty and need time to ease it. Moreover, women are sensitive, so you should pay more attention to her and prove it with practical actions. Don't expect chatting to solve the problem.