male colleague flirting at me at work

Ok well theres this male colleague of mine who I have been working with for a year now and in the beginning he kept repeating what I said and copying my actions and mirroring my body language which at first i thought it was where I was new and he was just getting used to me but then i friended him on facebook and when we'd work together he would make comments about what I had been upto, like if I put going to the gym, then overtime he started joking about getting my muscles out which was funny at the time but then last time I worked with him he reached out and rubbed my arm in a rather sexual way for a while and when he got told off for doing it he just made the excuse of well Im just feeling for her biceps. On a positive spin he has helped me at work by lending me his book and has left an open door policy saying he was happy to help, he has started lingering around near me and I have another job now just working across from the old job so he still sees me around, he is married so whats the game play here?

Well he's obviously flirting with you but if he's married he might just want a sexual relationship. If you want that too well go ahead make the second move and flirt back. If not then you should put a stop to his flirting cuz it might get you into trouble if for some reason his wife see's him flirting with you