For some context, im (18m) almost certain she (18f) isnt cheating, however i cant help but think its weird. She has a powderpuff football team "friendgroup" with guys coaching who i am friends with so i am pretty sure she isnt cheating. The weird thing is that she kind of keeps it secretive? she doesnt ever say she is going to hang out with them and she i guess does it in a weird way. Almost like she doesnt want me to know, which (even if its not true) makes it feel like shes hiding something. If i hint im annoyed she usually just gets upset and avoids it. One of my other friends feels the same, as his girlfriend is also on the team. If you have any other questions you would like me to answer, id be more than happy to respond, as i know im not great at detail explaning.
tl;dr: am i insecure thinking its weird she hangs out with her guy girl friendgroup in secret?