How do I erase her from my subconscious?

VIPPERs are not capable of dreaming, unless the dream was about mittens. Was your ex-girlfriend wearing mittens?

I usually dream about my ex-girlfriend as well, but last night I had a dream about murdering a friend of mine and hiding his body in a dumpster. I also had tea with a different ex-girlfriend while secretly quaking with fear that his body might be discovered and that forensics would implicate me as the murderer.

And that OP, is how I resolved not to murder anyone.

If you're a guy, beer and porn. Repeat until over it.

If you're a guy, hookers and blow. Repeat until over it.

If you're a guy, mittens and quality. Repeat until over it.

If you're a trap, mittens and quality. Repeat until over it.

If you're a girl, me. Repeatedly.

It's impossible. Proceed to leave thousands of messages and to stalk her.

It's hopeless. Commit a murder-suicide. This is the true man's way.