"how do i explain it to him"
the explanation will go over his head
you'll have to be bland and watery with your words
you'll say "i love you but i can't do this anymore"
he'll look expectantly at you
but all he'll understand is that you are giving up
not that he has emotionally beaten you to the ground
not that he will never be able to love you as much as you do him
and it will feel like a long f
a
l
l,
your adrenaline will frighten you
but what you must learn is that
love is give and receive
not give and give and give until you have nothing left
he won't understand that
he'll argue that you're just too demanding
but isn't that always his response?
to blame you?
Leave him and find yourself.