DO NOT issue an ultimadum! She wants you to! That will relieve her conscience because she'll feel you backed her into a corner. Have you considered getting her to move out instead? I know it seems counterproductive since she'll most likely go to him, but it may help. Close constant contact often wears away at fantasy more quickly than anything else.
Only you can decide whether you need to walk away for your own sake. There can come a time when it is too much damage to you to keep fighting, but no one can draw that line but you. All I can ask is, is your love for her worth walking through fire? You haven't said the "I do's" but you've lived them. And when my husband said "for better or worse" I know he didn't envision the "worse" I would put him through. He hung on because to him I was worth it (honestly I would've left if I were him). Is she worth it? Look back on why you were with this woman to begin with; she was your everything, right? There's a reason...is it still strong enough to fight for?
Sorry...just reread "she refuses to leave". Hmmm. You could pack up her stuff for her. Make the situation uncomfortable for her by refusing to leave too. You have your son, she has no right to think you should leave. And tell her that. This is your son's home and she cannot expect you to relocate him. if she wants her "new life" then she needs to leave, not you. It will be much more uncomfortable for her if you push back this way. it will force her to make decisions, decide how committed she really is to her fantasy.
The grass may be greener, but then again, it may also be astroturf. ~Amy C Brown
