Great that you could get the free advice. I know my county also has the same free advise. My L said they are good for simple cases and for helping with parenting plans, but when there is substantial assets involved, it is best to get an L involved in writing things up correctly. That is if one is doing everything uncontested. Contested is a whole new ball game and is what you are most likely facing.
You are at the similar point I was at back during Christmas. I was going to Mexico with the kids and was concerned that W was about ready to file a D against me. I ended up beating her to the punch by seeing my L before the trip and planned to file when I got back. I felt it important to strike first, plus, I wanted a little shock and awe to possibly wake my W up.
Right now there is nothing you can do to prevent it. Your H is going through with it. Just take your trip and enjoy the time with the kids. I hate to say it, but you will have plenty to worry about once you get back. Who knows, your L's counter to the filing may deliver a serious enough financial blow to your H such that it will make him see during a legal separation how hard his life is going to be if it goes to a D. I really think that you need to think of yourself having an advantage legally right now.
Take care of the legal aspects after your trip and there will be plenty of time to DB your butt off to save your M.
