Is it weird that I am actually ok and support my girlfriend's decision to go through with this?

My girlfriend and I have been together for 5 years. She is absolutely amazing and we have a wonderful relationship. She is very beautiful and I have become use to guys hitting on her and trying to get her number when she is at work or elsewhere with a couple of friends. I am not controlling or the overly jealous type and she respects and appreciates that. She is very straightforward and honest with me about everything and dosent like to hide anything. So a new single co-worker of hers has been abnormally persistent at this. I have always known that she is physically attracted to black guys, so I paid more attention to this situation. I asked her if she would like me to say something to him, and she said no she will try and take care of it herself like she usually does. A week later she tells me he has not given up at all. She said I just don't understand why he likes me so much when he knows I have a serious boyfriend that I would never want to leave, and especially after being shot down a thousand times. I asked her if giving in had ever crossed her mind if this continues to be an issue? She said all she knows is it's really becoming a lot more stressful because he is so nice to her about everything. I asked if she was attracted to him, and she said honestly I know I was at first but now its becoming physically stronger. I then asked, what do you think this guy wants from you? She said, if I give him my number he will probably want to date, and I know he will definitely want to start having with me! I said jokingly, it sounds like you are more than interested in that second part! She said, well do you think you could possibly be ok with it if I finally did let myself give in? I said I love you more than anything babe no matter what, and if it happens I will understand and respect your decision. She thanked me for my understanding and said she could not be happier with us. She said she feels comfortable now, and if he asks for her number again, he will get it!