I grew up with a large group of friends in our area..and 75% of them were guys...we were all like brothers and sisters and we still are to this day. Jusr because she has a lot of male friends it doesnt mean shes going to cheat behind your back. If she was attracted to any of them she would be dating them and not you so calm down and dont worry. Thats certainly no reason to finish it with her and if it worries you that much then talk to her about it, Honesty is the best thing and to be honest she will kinda love u and dig u more for the fact u care so much ur jealous. us women are like that!