English - I'm never forgetting

[Xmmm]

"I know that I am never lending money to that deadbeat again"
"I know that I am never going out with her again"
"I know that I am never eating broccoli again"

"never xyzing" is another way to say "never going to xyz" and is not all that uncommon.

What makes it sound a bit off in the quoted lyric, I think, is the lack of a direct object.

"I know I'm never forgetting to pay my taxes to the IRS again" sounds much more natural, right?

[Jon]

"I know that I am never lending money to that deadbeat again"
"I know that I am never going out with her again"
"I know that I am never eating broccoli again"

Probably it's my lack of knowledge but if I was speaking I'd say "I know that I am never GOING to lend money to that deadbeat again"
"I know that I am never GOING to go out with her again" and so on because "I know..." that I will or won't do something IN THE FUTURE, thus you add "again" in the phrase.

I'm forgetting ---> it's something I'm doing now
I'm forgetting again -----> it's something I'm doing now
I'm never forgetting ----> why on earth you wouldn't say "I'll never forget" instead being something that you won't do in the future?

In italian for example you would never say that sentence this way, it just doesn't work:

Io dimentico - I forget
Io non dimentico - I don't forget
Io dimentico mai - I never forget DOESN'T WORK
Io non dimentico mai - I never forget (perfectly fine)
Non sto dimenticando - I'm not forgetting
Non sto dimenticando mai - I'm never forgetting DOESN'T WORK

[Serpent]

Well, English isn't Italian. The continuous is commonly used to mean future. For example: Fiorentina is playing against Tottenham tomorrow
Tons of things look ungrammatical if you translate them literally from another language.

[urdubyoddballs]

Generally speaking, English uses the present continuous to describe future actions that either (a) have been arranged, announced, promised, agreed upon, etc. ("Fiorentina is playing against Tottenham tomorrow.") OR (b) are planned for the very immediate future ("I'm shutting down the computer now; do you need it?")

"I know I'm never coming back" and "I know I'm never leaving" both sound better (and get more Google hits) than "I know I'm never forgetting" because our travel plans are typically more amenable to personal decision and public announcement than the contents of our heads.

Of course, romantic songs do tend to be the exception to that latter rule, don't they?

See also:

• BBC Language Point: Present continuous for future arrangements
• Future Tenses
• The Future with Present Continuous / Will