It is unfortunate to say that men can be very jealous when it comes to love matters, i hope i don't offend anyone. But there is evidence to show that this happens. Usually when a guy goes astray and cheats on his woman, he may not say much but whatever he does will surely show eventually. When this happens the girl would probably set him aside and go silent, it's usually not long when someone will start a coversation with the girl, and when the ex sees that, it's automatic he will always be in your business, to know who your talking to, where you are, what your upto and so on and so forth. So don't be surprised when all the messages come into your inbox, he is just trying to keep tabs on you. They won't accept that they have lost you, and that they need you back. It's also a way of trying to apologise, but if you truly believe in your heart that you are over him just tell him so that he can stay in the know, and he will stop sending you messages.