Lera is your boyfriend's ex.

You and Lera have been friends for a very long time. Your mothers introduced you to each other. You were friends since childhood, you had a good relationship, you almost never fought, and you went to school together. She was an excellent student, and you were a good student. But at one point, Lera got a boyfriend. You were on good terms with him, but it turned out that Lera started to be jealous and often hid things from you. You decided to ask her boyfriend what happened to Lera, and he told you that she started to be jealous of her boyfriend's relationship with you. A few weeks later, you made up with Lera, and she told you that:

Lera: I'm sorry, I don't know what happened to me then, really, but I stayed with that guy.
You: why?

Lera: He started saying that I'm boring, too jealous, etc., but still, I'm sorry, of course, but I don't want to talk to you.

You: good

In the end, you decided that you needed to find out everything about her online or just make peace with her and continue communicating.