Sorry, but I'm not buying the story that you have girlfriends "by accident".
Break up with both of them. If you want to date, then just date. If you want to have a girlfriend, discover the word "monogamous". It will help you tremendously.
I dated a guy in college, who would eventually become my husband. He let me know from the start that I was not the only girl he was dating. So, I had a decision to make. He was honest with me - he was in college and he wanted to date and not have a girlfriend. He had this conversation with every girl he dated. I chose to continue to date him.