Hi, I'm sorry you are undergoing all this stress. Sometimes there are underlying issues in marriages and for the sake of the family, people just don't deal with them for years. There is a transition time where the children are almost grown and sometimes people reevaluate their marriages. Many act out and true, hormones can play a part. This time period might last a few years. Some people want to test the waters and see what they're missing (if anything). These are issues the people involved need to work through. Often, they live in a fantasy world for a time and truly don't know their own minds or what they want. When all this drama ensues, it can often be due to the fact the couple had simmering and unresolved issues for years.

I can only say from my own experiences in life, that each individual may want to consider therapy to sort out all their feelings and goals. There is no way to fix someone else's relationship. This has to be done through a process with the individuals involved. I can appreciate you have feelings and fears, but in the end they may choose to stay together. If not, then perhaps they find a new path to eventual happiness. I hope you can find support here. I'm new and trying to find advice for my issues in relationships - I hope we can all offer insights to give us peace of mind. Take care of yourself.