but I'm scared of the unknown in this marriage and outside it
I think this is normal. It is how I feel too and I am 16 months out from DDay. What helps me is to know that I cannot control my WH I can only control myself and how I deal with any future mishaps. Really we only have today. Maybe try and focus on a day to day basis instead of worrying about the future.
If my WH cheats again he knows where I stand now and it won't be next to him the next time he does it.
I am sorry you are hurting today (((huRtZ413))))