I have many friends around me who love fitness and often go to the gym, but I have never seen anyone cheating. Perhaps, you are worried that the coaches in the gym will be handsome or muscular, which will threaten you, but this does not mean that your girlfriend will definitely like them, and if you have no confidence in yourself, then you will doubt what your girlfriend does.
If you are really worried, you can also go to the gym with your girlfriend. On the one hand, you can see why your girlfriend loves going to the gym so much. On the other hand, more importantly, you can exercise and keep fit, which can also make you more sunny and confident.
Therefore, before there is conclusive evidence, don't be suspicious of your girlfriend, which will easily hurt the feelings of two people and give some people an opportunity. Be sure to remember that unnecessary worry is always futile and will only annoy yourself and each other. If you think your girlfriend has done something that arouses your suspicion, then you can talk to her aboveboard and clear up the misunderstanding. If you are just thinking alone, don't think, adjust and control yourself.
Fitness is a healthy and progressive life concept. Encouraging you to exercise with your girlfriend can not only dispel your doubts but also deepen your feelings, which can kill two birds with one stone.