Most Helpful Guy
Hey, I feel for you here, because this is where things get hard. It is emotional agony trying to get over an ex, which usually only time can heal. And roughly around the 5/6 month area we are back into routine and on our way to forgetting our ex an moving on. But in some case all that gets tossed away when our ex hits us up via text, social media, a friend or in person. Here's where you have to decide if where you are now is better without him. It sounds like he might want to try a relationship now. If you are at a good place in your life right now, don't mess it up by letting him back in so easily. This doesn't mean, don't talk to him an see where his heads at, even catching up is good but be on guard. He misses you at least, and is curious where you are in life. Possibly trying to see if feelings for him are still there. Don't fall easily.
Most Helpful Girl
take it slow, work out what it is that he really wants. Is he bored and looking for company or has he realised that he made a huge mistake and misses you from his life and wants to give things a second go. At the 5 month stage you would be in a pretty good head space and his just ruined that. Take your time you are in control. work out what you want and if things between you could ever be the same or better.