Be honest.

You love him.
Can't imagine life without him.
He's your best friend,
the person you always run to...

But,

He doesn't' make you happy.
You've never felt sustained happiness in this relationship.

And moving to DC,
getting married,
having kids,

Isn't going to change that.

Look, I'm not telling you what to do,
because **** if I know myself,
but at least be honest with yourself.

He's never going to be the guy who calls the cable company to dispute his bill.