Obviously choose between your girlfriend or that girl friends of yours. Imagine her playing with mostly boys, wouldn't you be a bit nervous when you don't know what she is talking about with other boys and why she would be interested in other boys when she have only you? She is crying becouse she is in pain confusion and inner fight and if someones pain annoys you especially pain of your girlfriend then that means you don't probably really care about her and see her as another girl friend more then actually girlfriend and dont take your relationship seriously. If you don't change and keep her in pain she will lose interest in you eventually and will not give a fuck about with what people you are texting with anymore.