You can unburden yourself to/on/onto me.

[Talab1234]

1. You can unburden yourself to me.
2. You can unburden yourself on me.
3. You can unburden yourself onto me.

Are all grammatically correct?

 

[emsr2d2]

Use "to".

Note that I have improved your thread title. A single word rarely suffices.

 

[Talab1234]

Use "to".

Note that I have improved your thread title. A single word rarely suffices.

The other two are incorrect?

 

[5jj]

The other two are incorrect?

The Are the other two are incorrect?

 

[emsr2d2]

If the other two were correct, I would have said so and I would have added that "to" was the most natural. I didn't do that. I specifically said "Use 'to'."

 

[Barque]

You can use "on" in a different context, for example if you follow "on" with what he was unburdening himself about or the place where he did it.
He unburdened himself on the subject of his marriage.
He unburdened himself on the flight.

As for "on" followed by a reference to the person receiving the unburdening, I've heard it sometimes, and it's comparatively casual. I agree "to" is the best choice.

 

[Tdol]

How about something like this:

You can talk things through with me.