my gorgeous gf and this guy are close friends. their families know each other. when i am out of city for work, sometimes she asks my permission to go out wid him. they have gr8 chemistry.
few days back they went out wid my permission. i asked her what they did? she never hides anything from me and told me what happened.
1) her training institute and his office are in the same building. once her class is over she met him. he gave her a queens welcome, finished his work quickly and they started out on his sports bike.
2) they watched a movie and had lunch. she played with his hair as she likes it. then he took her hand and told her fortune. she said he studied palmistry.
3) she asked him to teach biking and he taught her for a while.
4) they played bowling game. after that they played snooker. he taught her as she doesn't know how to play.
5) they went to a pub, danced together. he was holding her hands and waist. she asked me "are you feeling bad that he was holding my waist"? i said "if its ok for you, its ok for me". she replied "i dont have any problem. its ok for me"
6) he dropped her home and while leaving he said "today you are looking sexy". i asked her whats your reply. she said she looked at him seriously. he smiled and left.

are they flirting? can she flirt/love/have s*x wid that guy when she is in love wid me and planning to marry. am i worried unnecessarily?

I would say, you have not seen or have not been in contact with girls that are really friendly with boys. When families don't ask or expect from their grown up childern to stay away from company of opposite sex friends, girls and boys do develop this kind of healthy relationship.

Its just that you have not been friends or came in contact with such a girl, you are taking it hard to swallow. I would say, normally, she would not have asked for your permission to meet that guy. It is good that she asked you first.

Human Mind has a tendency to look for the missing link, negative things. We totally neglect 100 positive things happening to us and constantly cry about 3 bad things ! So, grow up and broaden your vision.