Just checked out the lyrics & he mentions 3 things that he'll never do followed by "...But I won't do that".
"I'll never lie to you"
"I'll never forget the way you feel right now"
"I'll never forgive myself if we don't go all the way - Tonight"
Not sure if this is the right answer but it's a thought.
Oh yeah, Shatnerfan's right it is screw around.
By the way, there are other things he says he'll never do, I just forgot to look at the second page!..(it's a long song!)
i firmly believe that the answer to the said question is that Meatloaf will not tell his lover that he loves her. thank you for listening. yours faithfully s