None of us is Super Woman. We all have our breaking points. Part of surviving as a supporter is learning those breaking points, anticipating them, and changing direction. And that may mean not being strong 100% of the time. It may mean asking for help. I tried to stay strong for far too long and nearly destroyed myself in the process. Reaching out and discovering I had a support system in friends and family saved my life. Continues to do so. I do them no favors in not taking care of myself, even if that means putting my H and his issues on the back burner from time to time.
There's no shame in hitting bottom so long as you do the work to pick yourself back up. So do it. Pick yourself up. Go to therapy. Work out what is going on in your head - not your H's - but yours. Your H is just going to have to fend for his emotionally self. Hopefully he can put some of his stuff aside to help you, but if not, you don't need him to. You have yourself.
Be sad. Be confused. Just for today. Then go to therapy tomorrow and face down the dark and start figuring it out. You CAN do it. We're here if you need to scream at the dark/howl at the moon/rage against life or any other metaphor you want to insert here.