I too had a situation where a guy was showing me attention and I know how good that feels!
What I did was sincerely and honestly thank him for the gift he had given me of making me feel attractive and knowing that I am really worthy of a man caring for me. I then told him that I still have hope right now of perhaps restoring my M, and am not ready to move away from that, but that did not in any way reduce the appreciation I felt for the priceless gift he had given me and that I would forever be grateful to him for that.
This man still flirts with me and tries to get me to blush, but he has become sort of a friend, and a real salve to my ego. One day, after a backslide with H, I was really down and had a "claustrophobic attack" on the bus and had to get off suddenly, and ended up calling H to come get me. I found out the next morning that this man (J) got his car and came back to look for me because he was worried!
So, I think that, most times, honesty is the best policy......and of course if you can do it in a way that makes the other person feel good about themselves, that's ideal!
Now, if the guy won't stop IM'ing you, then you may just have to be "brutally honest".....
Take care!
TJ
Me45,H49 D24,S18 M26,T28 Bomb 3/19/08 Sep 6/23/08 EA/PA with Secretary 2007-8 3/2009 H moved in w/OW2 7/2009 Let him go w/Love. 8/2009 Legally Sep'd