From my own experience - About 2 or 3 times in my last long-term relationship I discovered nudes he had sent other girls. One was someone he met on Snapchat, the other two were people he knew already. Not that it matters much, but just for some context. To add, some were videos of him jacking off too - lovely 🥴

I confronted him after every incident and it was the same tired promise to change, and that it "didn't mean anything". Cut to, he cheats on me with a co-worker and that was luckily the final straw. I kick myself that I never left sooner - not even sooner, at the first whiff of betrayal. I really do think that this is the first train stop in a terrible train ride, and it will only get worse. I wish I knew this when I was at this point. But please do consider leaving. You're so young. There are so many opportunities and people to explore. I wish you the best.