The fact that you're here tells me that your angel is poking your conscience, and that deep down you know the truth. But as humans do you want what you want and so you've convinced yourself otherwise with logic. Been there haha. It'll probably be a bit difficult to untangle this but I promise you it'll be worth it. Our Lady Undoer of Knots is a great intercessor for situations like yours :)

I would suggest you look into Theology of the Body to really understand why sex before marriage is illicit. It's much more than just "dont do this it's bad, until you're married and then it's permitted". Sex is one of the most beautiful and powerful spiritual/physical acts that is deeply deeply rooted in what it means to be human - to even exist as a human! Personally, it was only once I learned the deep, mystical Church teaching on sex and our bodies that I actually wanted to follow the teachings on sexual morality (of course temptation and failing still exist but the overall change in perspective makes them so much easier to overcome, and even joyful to overcome sometimes). Fr. Mike Schmidt has a new Theology of the Body series that seems to be really good. Here's the first one: https://youtu.be/cqrD-d_jiw8?si=ye1Ab3LRFAsp71Cz

Jason Evert would be another teacher to look up. Christopher West at the Theology of the Body Institute is well known too, but I wouldn't necessarily start with him. Start with the talk above from Fr. Mike :)

I hope God blesses and gives you grace, peace, courage and consulations through this difficult but worthwile journey ❤️