I#ve seen this quite often. They just stop responding and cut people out. Not always just romantic relationships, friends too. Someimtes I can see their phone, some friend tries to get in touch with them, they read all the messages and then just ignore them. Or if there is someone present, they say stuff like "Oh, I*m not talking to this one anymore". I don't see guys ghosting unless they're depressed or it's a really crazy ex (and even then they respond sometimes).