Is it okay for a close friend to date your ex?

I married my friends ex. Bite me. She che'ated on him, he found out. They broke up. He relocated to the US, I had relocated years before he did. We bumped into each other in New York of all places. I gave him the cold shoulder at first because friends ex and all but he was quite persistent. I never gave him my number but we hadn’t stopped being Facebook friends. Who uses Facebook. My friends list has been the same for years. That’s where he started his chase from for months before I gave him my number. I resisted but abeg this guy was and is a really great guy and I wasn’t going to make the same mistake my ex friend did. Letting a great guy go. She cheated on him for goodness sake.
My friend then used to say she had his mu'mu button and he was too good. She didn’t know what she had and she cheated on him with a “bad guy”. I guess her boring good guy was my gold Prince Charming. He’s an amazing husband and father. The best thing that has happened to me. I was going to tell her when we started dating but he said I shouldn’t. We lived in the US, she lived in Nigeria so it’s not like it was in her face and there wasn’t any social media display of affection. Besides we weren’t close like that anymore.
A mutual friend saw us together at a party and told her. She called (someone that hadn’t spoken to me in over 6 months) and cussed my life out or she tried to. I was on the phone with her for all of two minutes and I hung up. She called tire, sent me messages on Facebook and IG, I blocked her, then she started sending emails. I blocked her too without reading the emails beyond the first line. I knew immediately it was her. She kept opening new accounts to email me and I kept blocking her without reading. Babe went cra`zy and cra`zy. She kept expecting a reaction and my boyfriend said I should ignore her. If she has liver, she should send him a message and he will handle her.
All this while, she was bad mouthing me all over Lagos, forgetting to tell people that she che`ated on this guy. I didn’t even address it. People called to ask how far, I told them I wasn’t talking about it. I’m with him, there’s nothing she says or does that will change that and giving her attention is feeding her crazy. Those who chose sides, I nicely cut off. I didn’t even know my husband had bought the ring before the drama and was just waiting for the right time to propose.
We got married under a year after the fiasco. Beautiful wedding which I didn’t share on social media and 3 years and twin boys after. I have zero regrets. He loves me, I love him. My in laws adore me, I adore them. My loss would have been another woman’s gain if I had said no to him because how was a “friend’s ex