My girlfriend has kissed another girl, and she told me she liked it, what do I do?
	
	
		We've been dating since December and I consider very special to me, she says she does and reminds me how much she loves me as I do to her each day. 
About the beginning a June, we begin to argue a little, and after graduation around July ,I feel like she is acting differently. All through our relationship she had secrets from me about drinking, weed, or her X. It made me miserable. 
Now she kisses a girl at the girls farewell party, and tells me a week and some days after, telling it was good and she like it. She doesn't believe that it's cheating, and that cheating is only another sex or sleeping with your sex. 
So I am very upset, and shocked, and am considering the fact of breaking up, but don't believe I should because I love her so much. She's telling me that she doesn't know what to do and she wants to have fun and experiment too but I consider her cheating terrible, and won't stand for it. 
She wants me but she wants fun too. Should I forget about it cause it's only a girl? The next time she does that dump her on the spot? Should I dump her now? Is this normal will she be with me and I can live happy? What's the best option I thought it through and it hurts so much cause I don't want to lose her but I don't want to be cheated on... help me!
I don't need people telling me it's hot so it's okay.
Thank you for your time.