As i stated to another person on these forums, throughout the whole of your life, your partner is gonna have female friends, same way you will have close male friends. If you trust him enough, then the other girl can do what the hell she wants, coz at the end of the day, he's with you. Thats what you need to remember.
My girlfriend was extremely close to her ex boyfriend for years into our relationship, i had to see him about 2-3 times a month for 3years. They would hug when they saw each other, make personal jokes which only they knew about, and deep down it killed me, almost to the point where i wanted to drink myself stupid every day. BUT she told me, that at the end of the day, she had the upmost respect for my handling of the situation and that most blokes would have knocked him out. (what all my mates were telling me to do). I allowed her to meet him on her own and go clubbing, go for meals, coz i truly trusted her and loved her to pieces.
And like you say yourself, it actually keeps you on your toes, you make sure that all the clothes you wear are nice and you dont ever let your appearance drop. But unfortunately its something you will have to deal with personally, its damm hard and extremely painfull, trust me, even to this day when his names mentioned inside i die and i wanna kill him BUT inside i knew she loved me and would never ever cheat on me.
If anything when you meet her, give her a nice big smile knowing deep down at the back of your head, its you he loves, its you he spends most time with, its you he will probably wake up to in the morning and she's no where near getting that special bond you have!!!!