Feeling lost

Long post....

This is more of a vent but i dont know what to do. I have been w/ my spouse for 20 years, married for 17 of them. We had our shares of hard times, some times more then I thought we deserved. Nonetheless I definitely have my faults as does he. After another blow up on his end, he tells me he is leaving in 3 weeks. I get why he is frustrated he has a lot on his plate. Every argument has been the same the threat to leave me and our kids. One has grown used to his ways and puts on stone wall face to deal with it. The second, who is the youngest has a melt down everytime he says he going to leave. It breaks my heart to see the kids act this way. We don't have family support, all either work or dont live near us, so it's been us dealing with everything. I feel a bit of peace for my mental sake. Sadness for my kids knowing dad won't be home anymore. I truly dont won't him to go as do love and care about him. Any words of wisdom or advice would be helpfully.