This might be hard to swallow, but your ex might be a fast mover and want to get on with his life by finding a new romantic partner. Whether he intends to find something casual, a friendly companionship, or a more serious relationship, he wants to move on.
Nowadays, online dating sites provide an incredibly easy way to accomplish this by giving people access to a large group of people who are generally looking for the same thing. All he has to do is find a dating app, create his profile, and start browsing for matches.