Hi, Lillie, and welcome to SR. Glad you found us here, and I hope you find the help you're looking for.
It sounds like you understand that he has to be the one to get sober and that you can't do it for him, and that's a big step right there, one that has taken some of us here a long time to get to. You mention that for now, he's functional and hasn't lost anything (well, other than his partner and his child...). As you'll see in your reading here, alcoholism is a progressive disease, and things will continue to go downhill, so it's smart of you to get off the train now rather than when the inevitable wreck really begins.
Reading as much as you can here, including the stickies at the top of the page, is a good way to educate yourself about alcoholism as well as to find support for yourself. I'd second the recommendation to get to Alanon, also. Having some in-person support as well as online here has been a good combination for me, and it could be for you too.
Again, glad you made it to SR, and I wish you strength and clarity as you move ahead.