I have no problem with Clark and Lois having sex.It was by mutual agreement so to speak. He should have stayed the night. Clark may not have told her his secret,but he has not lied about his love for her.
I do have a problem with Lois's failure to recognize him at this point.

"I'm red-eyed, tired and drunk" Teri Hatcher
"Fun will now commence" 7of9