I’m in a huge mess and need an exit strategy. Caught in a web of cheating, guilt, and subtle threats

I’ve been talking to (X) for a few months now with the intention of marriage. He really loves me and promised to make things official in a few months. He’s super serious about it and wants me to love him back, so I’m giving him a chance—I mean, why not? Plus, my mom knows about him, so he’s basically considered my future husband.
But then we took a 3-month break, and during that time, I got really close to this guy from uni, (Y). At first, we were best friends, but then things turned romantic—car make-out sessions, cuddling, and intimate physical moments (nothing fully sexual). When (X) came back with those same serious intentions, I felt so guilty. I tried to pull away from (Y) and told him I couldn’t do this anymore because it felt like cheating. But (Y) totally manipulated me, saying, "It’s not cheating since you guys aren’t officially engaged yet." He kept calling (X)’s promises fake and was constantly badmouthing him just to mess with my head.
Meanwhile, (Y)’s best friend, (Z), stepped into my life. He slid into my DMs offering academic help, wanting to be friends, and even offering to be my "life coach." By the way, he already knew about me and (Y) being friends with benefits, but he didn’t care. Instead, he told me that (Y)’s feelings were purely physical because of my looks I told him I already knew it wasn’t love and that it was just a situationship with no real meaning. But then (Z) started bashing (X) too, trying to get me to leave him for the exact same reasons he mentioned about (Y), while trying to present himself as the better option.
Over the course of about a week, I got closer to (Z) and our friendship grew stronger. At the same time, I gradually distanced myself from (Y) because he started asking for nudes, hinting at sexual stuff, and getting super jealous of my closeness with his friend (Z). As for (X), my relationship with him is stable and calm since it’s serious.
Then (Z) invited me to his house to tutor me. (Honestly, I was so creeped out by how hard he was trying to get close to me. He literally learned a whole subject he wasn’t even taking this semester just to teach me.) I guess I made a stupid mistake by actually going to (Z)’s house. After studying, we ended up having intimate moments (no sex, but lots of touching from him). I felt so lost that I even asked him for a hug when I was leaving... I don’t even know why I did that. Our hangout was full of laughter, jokes, sharing childhood memories, and intimate moments. The thing is, he jokingly hinted that I’m a player.
To make matters worse, (Z)’s family has major political power, his dad holds a high government position. He told me he found out one of my new friends is using drugs and threatened to use his power against her, telling me to stay away from her "or else." He was acting like he was just trying to protect me, saying, "Just obey me and you won’t get hurt." But I am genuinely terrified because he holds deep secrets about me that could ruin my life if exposed. Even though he hasn’t explicitly threatened me yet, I feel so paranoid about him meddling in my life. He constantly repeats phrases like "let me control you" and "listen to me, whatever I ask you." I’m terrified that my strict/religious family will find out about any of this, or that (X) will figure it out and leave me.
Did I cross the line into real cheating? What’s the safest, smartest way to cut (Z) out without triggering a disaster? And how do I make sure (Y) is completely out of my life too, especially since he still gives me looks at college?
I just want this whole nightmare to end, to be a good and faithful partner to (X), and to get rid of the burden of these secrets. On top of that, I need to know how to distance myself from that friend, because she’s going to open the door to a whole lot of trouble for me.
All of these behaviors are extremely serious because I live in a conservative society that criminalizes removing the hijab—especially since I do it behind my family’s back—and also criminalizes exchanging affection, kissing, and being alone with a man. For the record, I’m non-religious. I left Islam a long time ago and I’m living a dual identity just to adapt until fate allows me to leave. And if you’re wondering why I’m holding on to (X), it’s not because I love him, but because he’s open-minded—meaning he’s not practicing at all and he’s the best choice for my situation as a non-religious person. With him, I can finally remove my hijab, since he doesn’t mind me being myself, and I can live my dream life if we marry.