Please help me out

I am married for last almost 10 years now and no problems in my family by god's grace. But, recently, since last one year, got closed to one of my female colleague who is a divorcee with a kid, And she works in different campus and we rarely see each other daily.

she asked various types of small helps and i helped her as i felt pity on her. in the mean time, we had hours and hours of talk all general things and got more close.

She has shared all her life stories and i felt very pity about the broken marriage. etc.,

But since last few months, i am getting attracted to her dresses/hairs etc., but i never commented anything about how she looks, but she always boasts herself about her looks.

So, My problem is that i am seeing her face/her style etc., in front of my mind/eyes all time and i am not able to concentrate on any other things,

Need to get rid of this immediately.pls help.

And, generally I never initiate any discussion on my own, she use to contact majority times, and tries to convey all her kid/brother or future plans etc.,

Even i tried to block her, but later felt it may sound rude way of disconnecting friendship.

request you to go through the above and give your valuable advise and i need to come out of this and forget divorced colleague completely.

would really appreciate and I am eagerly waiting for your positive reply,