how do you know if its a mlc vs. H wanting out?

[Cadet]

i keep blaming myself for his leaving.

This is not your fault.
It is him, this is now YOUR time.

I just want so much to fix this.

There is no fixing this.
You must let go.

he even told me that a few weeks ago, "just let it be for awhile".

He is giving you good advice listen to what he is saying.