You've been doing this long enough, and self reflecting and self-caring deeply enough to know when you are running on emotion and reactivity, and to know when you're making a practical change that best suits you and your future goals. It doesn't sound like you're in urgent financial difficulty, so you can afford to take some time to mull over your decision and make it slowly. And yes - make it in privacy. There's no need to discuss this with your H. He isn't acting as a husband, which means he doesn't get the privilege of collaborating with you as you shape and build your life.
It sounds like you have a good short term plan - help from your sons, less 'family' time with H and some boundaries about the time you spend together when he's there to work at the family farm. These are ways you are setting boundaries and protecting yourself for the next year, which is when your 17 yo will go to college, right? They sound sensible to me - and what's great is that you feel you can do what you need to do no matter what your H's response is or isn't.
Do you have a longer term plan for your future after s moves out? Have you had legal information about what you're entitled to in terms of maintenance and a settlement, should it come to that? Are you worried your H might get into debt or otherwise act irresponsibly and do you have a need to factor that into your decision making process? I hate to ask this - but if there's an OW or a risk of one, do you need to wonder what might happen if he creates another financial responsibility for himself and how that may affect your youngest's college tuition? You might not want to file yourself, but knowing what the future might look like if your H does decide to file might help you prepare for that. It might also be a positive process for you. I have been really inspired by the way that Yail has been dreaming about and moving towards her ideal future on her thread. I'm not there yet myself but I look forward to getting there!
