I think your XH with the woman was partly because of your internal fears (you'd had a fight so you were scared) of XH leaving for another woman, but I have to say that these dreams where spouses say they will leave, usually herald R problems and they usually do leave.
The lake probably doesn't mean anything as it is part of your family's property so it is just in your subconscious. The house represents family matters and home, and your spiritual body but meanings can vary according to the state of the house and it's function within the dream.
The canoe represents your R with XH and the fire is a sudden dramatic change in your life, usually a break up or something really major. The fact that you got through the fire without being hurt is a good sign, this means you should be able to overcome any problems you have and if the water in the lake was calm and clear, this is good and calmer times ahead for you.
