Should we break up?

My girl friend last month left to visit her family for a month… So she went out and made some new friends.. Well she ended up meeting a guy that she likes and has told me that she did go out with him a few times the month that she was gone.. She admits she is attracted to him but she hasnt told the guy she has a boyfriend..On top of that when she came back we went on vacation and told the guy she went on vaction with a friend not her boyfriend. So she said that she was confused and thinks what would it be like to be single and date other people… and if I ever wondered that.. I said no… She did mention about maybe taking a break but I said if we took a break I wouldnt come back… She says shes loves me and doesnt want to loose me… But I said I wouldnt have handle the situatuion in hand like she did… I love her with all my heart but I just dont want to be waiting around while shes trying to look for other people.. Shes says she is intrested in meeting new people and just seeing where it leads but at the same time doesnt want to loose me… I said well you cant have both.. So what should I do???