You can search my name in this forum if you'd like to see my on-again-off-again posts about the 3 times DH has left me and my step-son (his son) over the past 10 years. He's in the process of moving out of the house and has been living in the garage for the past 6 weeks (his choice so he can drink and smoke pot all night). He rarely communicates or interacts with us during that time and you know what? There is barely a difference in our lives in a lot of ways and I'm also noticing positives.
I'm still the person doing the shopping, cooking, cleaning, transportation to activities, helping with homework, etc. But now I'm also the person accepting invitations instead of waiting around to see if DH wants to do anything. I used to turn down invites with friends (including friends with kids) in hopes that DH wanted to do family things but he rarely did. It's also nice to not have that lingering hope that he MIGHT help with the housework or the transportation (both of us work full-time). My DSS and I have had so much FUN these past few weeks even though we are also sad occasionally that DH is making this choice.
My sister used to tell me that I'd be all right regardless of how things worked out. It's being in limbo about the choice. It's kind of like ripping of the band-aid. The dread is worse than the actuality.
You're not alone.