Hi, Jeff ~ Would you approach it as a request for a separation or divorce? Because what I was kind of picturing was:

"I've been really struggling with what to and have been considering suggesting a separation, because I need more than what we have right now."

Said calmly, but letting her see that this is painful for you.

This lets her know that the situation is really, really serious, but also leave the door open for some action on her part.