Very good advice RobX. The only other thing that I could add would be to include that you are not going to share your spouse with anyone else. If she choses to be with someone else, you can not stop her. Make sure to include in all of this that these are her choices that she is not making. You can validate all she says, but do not let her place the blame on you. You can expect her to use major deference to put it back on you.
