What's worse is the feeling that he is providing this fantasy for another person. OP is enjoying my fantasy.
OW may be getting "a" fantasy, but not yours. Does your fantasy include substance abuse, adultery, etc?
My IC told me that the OP gets the child acting out, only the side our WAS show them, not the real person we loved for so many years...we got/get the whole person, and, unfortunately, that includes the damaged part that expresses itself in MLC, escape, avoidance, and so forth. The OW gets the immature H that wants a band-aid, not the real H.
I struggled with this for a long time (and still do at times)...but after several of W's OMs......my IC and the infidelity advice here and elsewhere is proving accurate. I have been there, I feel for you...please just remember that OW "ain't getting sh1t" in all reality.
H is in there somewhere. Just, as everyone says, the alien has taken over. This betrayal is part of the script, the process...like a teenager breaking away from Mom and Dad.
Just work on you, be the better choice...for you. The OP will usually show their true colors, and hopefully our WAS take off the rose-colored glasses long enough to "see", sooner rather than later.
Hope this helps some...
T^2
In the depths of winter, I finally learned that within me there lay an invincible summer. - Albert Camus
Uncertainty is the very condition which impels people to unfold their powers.-Eric Fromm