Is it wrong for me to demand my girlfriend to delete people from Facebook?

[Joseph Louis]

I know it's only a social network, but it bothers me that my girlfriend has some guy that she had a thing for way before she met me. She told me that she will not delete him whatsoever. I have been respecting her through the rules that she has been applying to me, but I honestly feel that it's wrong for her keeping him as a friend on the social network. Should I suck it up and let her keep him, or should I continue pushing her to eliminating him? She wants a good excuse in order to delete him. I find that my excuse of uncomfortability is good enough.

Thank you in advance.