Good for you, Liz for taking pro-active steps.
As to any requests or "offers" you might make to him - I'd suggest just not saying anything at all. First, anything you might say comes from your current perspective and feelings, and the key reason for your separation is to figure out who YOU are outside of the confines of this defining marriage. So you need to take the time to reflect alone before you'll begin to know what the next step is together.
Second, any offer for joint counseling or whatever "if he does X, I will do Y", puts you squarely back in the middle of his life, monitoring his recovery or non-recovery... I'd leave him to do whatever he chooses to do without comment or even much observation on your part.
You have my best wishes and support.
ShootingStar1