lesbian problems

Im 17. Okay so me and my girlfriend have been together for 2 years now and she's super obsessed with me in good and bad ways. I need advice on a whole bunch of things. I've cheated a couple of times for my own reasons but I need help now because I'm suspicious she's cheating. But there's so much more to say lol like I can't even type it out 😩 or put my feelings into words.