HELP WITH EX BOYF!

So my ex and I have been broken up for a month now. He broke up with me because he wasn't happy, not because I couldn't make him happy but because the situation we were in was hard for him (personal reason). 1 week after we broke up he posted a photo in his car with another girl. It was hard for me seeing he had already moved on seeing as we were together for nearly 3 years. This week I posted a photo holding hands with a male friend and then next day he had 2 of his friends try to get in touch with me (added me on social media and prank called me at work). The day after that he messaged a friend of mine asking if he can call him to talk about the photo I posted. When he got off the phone my friend told me my ex made him promise not to tell me what they spoke about by I managed to get something out of my friend: he asked my ex if he misses the idea of saying me or actually misses me? My ex said he misses me. Also he told my friend that the girl in his post is a friend and nothing more although he knows it was wrong.