How to use can't come soon enough?
"This divorce couldn't come soon enough" (link https://youtu.be/tBDrKj0x95Q?t=12m52s )

A little introduction... Once Michael wife's had dumped him for a week or a month already.
As far as I know Trevor would never wish bad things to Michael, because they are tight like son and dad.Trevor is not beneath it ever.
I have tried to find the meaning of "can't come soon enough" and there was said:
it means an huge anticipation by someone before some event, but because Trever never wanted him to divorce I am wondering if it's kind of Trevor's wondering - why Michael wife's didn't divorce with him earlier.
Am I way off? Is there difference between can't and couldn't come soon enough?

Question

How to use can't come soon enough?
"This divorce couldn't come soon enough" (link https://youtu.be/tBDrKj0x95Q?t=12m52s )

A little introduction... Once Michael wife's had dumped him for a week or a month already. 
As far as I know Trevor would never wish bad things to Michael, because they are tight like son and dad.Trevor is not beneath it ever. 
I have tried to find the meaning of "can't come soon enough" and there was said: 
it means an huge anticipation by someone before some event, but because Trever never wanted him to divorce I am wondering if it's kind of Trevor's wondering - why Michael wife's didn't divorce with him earlier.
Am I way off? Is there difference between can't and couldn't come soon enough?

Answer

No, no difference.

You're pretty much right but it usually means that the person couldn't wait for it to happen, and has wanted it to happen for a long time.

It works also when talking about someone else. "For John, the start of the football season can't/couldn't come soon enough." Can't/couldn't depending on what tense you're talking in as the narrator.