My girlfriend has kissed 5 lads now?

the first 2 she kissed she forgot we were going out and just randomly kissed them, the 3rd one she was drunk and in a park and he shoved his tongue down her throat, and the 4th and 5th were last night at a party, she was drunk and at a party whilst i went out for a few minutes she kissed them, what should i do because its bringing me down yet, i do love her.