Keys for Room 21

I'm only feasible
I'm only beautiful and lovable
 in the pitch black of the motel room
 I'm checking in for keeps,
 so check the windows and draw the shades
 secure, make sure the deadbolt is driven all the way through
It wasn't that you didn't want me
 just not in front of the others
 I can appreciate the discretion
 since I live my life undercover
Why kiss me like today's your last?
If you're satisfied
 then why are you going back?
How can I keep you here
 in this rental room of secrecy?
 You live in the lush manicured hills
 with your well-to-do hubby
I'll be here next week
 in my convalescent cubby
 In room twenty-one by the highway
 The only way she wants me