Chatting with my girlfriend, her ex-boyfriend called her, but her girlfriend didn't answer. She texted back and said she was busy now, and then called him back. What should I think?

What else can you think of? Just think about it ... If it's your ex-girlfriend, you won't waste your time with your current girlfriend, but your feelings are not there. Maybe there's something wrong. No matter what angle you take, you won't call her back. Since your girlfriend will send this message in front of you, it proves that your girlfriend has nothing in her heart, otherwise she will reply privately ... Relax, it's nothing. Love needs tolerance and understanding. Sometimes you change places.