Don't get too distressed...look up psychologists in your phone book. Call as many as you need to, ask them if they are a solution-based counselor and are they pro-marriage. If you find one, please make an appointment...asap. You really need to talk to a professional.
Don't set any boundaries at all...my bet is that your W is more unhappy about her career and herself - than whether or not you are strong enough...IMHO.
Please call someone, you really can't afford to wait...
