I will not call back tonight. I won't call back actually. Next time he calls, I'll sound pleasant but get off the phone quickly and act busy.
Now you're getting the hang of it...
I would change it to..."I'll sound busy but get off the phone quickly, but be cordial"
No reason to sound happy to hear from someone who says they want out and who is with someone else. More like "happy, but happy to hurry up and get off the phone, no time to chit chat" (big difference)