Falling into this severe sadness that makes me feel physically exhausted

Hi everyone this is my first day here. I was desperate to find something or people I can vent to because I'm literally driving myself crazy. I'm currently in a 18 year relationship. For the past 6 years my significant other hasn't contributed much financially because he wanted to leave his job. I've been holding him down supporting my family financially while he figures out what he wants to do with himself. He recently started working again doing great for himself. But I still find myself paying our bills and taking care of our kids thank god they are teenagers which makes it a little easier. He's also been ignoring my needs but doing everything his mothers asks of him. mind you she is in good health and perfectly capable of doing things on her own. I feel like she is taking him away from his family. We own a campsite which was our getaway and he bought his mom a trailer 2 years ago at the same place. She saw another one she liked last month and he bought her that one too just because it was better than the one she had. But he is not contributing to his own family (my children and I). He actually been staying up there with his mom and leaving me home to take care of all responsibilities. I go up on the weekends when i'm not working and he won't even acknowledge me. I probably said too much just now but I just don't know what to do with myself and how much this is hurting me. Sorry for the long paragraph guys