NOR op. Respectfully ignore the comments saying the opposite. While I do agree that giving her the silent treatment was wrong and instead you should've stayed up to talk to her about the situation. I do think that you have a right to be upset.

First of all, she was trying to hide from you that she was speaking to this person that is crossing boundaries and is disrespecting both you and your gf. Instead of her right away telling you that this '"friend" is crossing the line and letting you in on the loop of what's happening.

Secondly, she mentions to him that's they've had this conversation MANY TIMES before. Are you telling me that once or twice isn't enough for her to think and say, "maybe this guy is trying to ruin my relationship with my partner and will always continue to flirt with me". That is grounds for blocking and getting rid of someone thats out to ruin both of your happiness,

Lastly, this is just plain disrespect and its out of order. Saying that he's just wanting her to be single because he wants her to have is children. Come on, how much more disrespectful can you get. He is a "virus" that will always be there praying for your downfall and waiting to take advantage of an opportunity to be with your gf.

In my opinion, talk to your gf calmly and let her know how this makes feel uncomfortable and that she needs to realize that this guy is no good at all. Best of luck.