I am apparently a homewrecker

An old BF I have know since I was 11 years old has been emailing with me. We've always stayed friends, even when we both married other people.
And now that we're both divorced and email again, what's the big deal? We hav even chatted on the phone a few times while I've been recovering from all those damn surgeries.
I just got an email from a woman who claims to be his SO and she's pissed!
"I've had a difficult life. Abandoned by my father, an alcoholic mother, and abusive marriage and a disabled son. Go ahead and have him but just know that you have ruined my life! But then, it's all about you, isn't it?"
I don't have one freaking clue what to say. I am such a slut KWIM?