I need some Information about how to catch someone or know for sure?

Me and my GF recently broke it off. She got a call from an old flame and she started treating me like I was her worst enemy. This person lives in NC she's in Upstate New York. She owns a home and so does this person in NC. They are both older. She stopped emailing me and told me not to bother her. I want to know for sure if she's with this new one or what's going on. Is there any way to find out for sure? I've asked her but she's a private person. Usually her relationships don't work out. She is controlling and usually they run for the hills. Any input would help me thanks.