Going to be 100% honest because thats the only way that this will help me out because I’m being a billy beta and thinking about this shit too much, need some advice.

Im 19 Male, upgrading some highschool courses to have the option to get into uni one day. I LTR’d this chick (18F) about 8 months ago. I plated her for about 4 months before on and off, and finally decided to LTR her after she showed me some green flags (good sex, sucks my dick whenever, cleans, cooks for me) About 3 months in I admitted I started getting lazy and gaming too much, around the same time my LTR started talking to an ex fuck who she called her ‘good friend.’ Not sure what really happened but they hung out once with her and her friends as well. Basically I think she cheated and there are a lot of signs that she did show which I’m not going to get into unless you guys ask me otherwise. Around the same time I picked my shit up, told her to stop talking to her ex because thats disrespectful and I just dont put up with that shit, started reading TRP a lot, working out almost every day, started acting like her daddy instead of her boyfriend, and basically all of the TRP shit such as dread, showing her my SMV indirectly (which is definitely higher than hers) and talking to other girls. Ever since I’ve been doing these TRP things the relationship has been really good. She blows me quite often, shes jealous of other girls I talk to, is always in her feminine energy around me, and has showed no signs of her cheating before if she did at all. But the dilemma is that I’m not 100% certain if she cheated or not, and I’m unsure whether or not I should give her the ultimatum to text her ex somehow and ask if they hooked up or I will break up with her, or cheat on her with potential plates who have been asking to hang out with me a lot recently and get that feeling of IDGAF if she cheated or not and that I’m okay not knowing.

TL;DR I was a billy beta for a while, LTR may have cheated, picked up my shit, am somewhat alpha now and she is obsessed with me, unsure if I should give her the ultimatum or cheat.

And yes I understand its beta to think about this shit at all and that I should not even give a fuck, but the signs are just too obvious and its at the point where its not even insecurity anymore.