Mare i think you see the "enthusiasm" from separation stemming from your allusions to her not being interested in your feelings, or talking about your issues.
if you and her were rowing at least, even if it were in a dysfunctional way, that would be different. but it sounds (from your description) that she just really can't be arsed with you. and that means there's really no recourse iyswim. hence people saying "explore your options re: separation".
that's not to say that you can't at least try to salvage this.
i think you definitely need counselling. i would put money on you having had dismissive or critical parents. you sound like you don't like yourself, are vaguely disgusted by the fact that you have normal human needs, and are utterly terrified by the idea of conflict.
counselling would probably assist you in dealing with these issues. i think if you did, you might command more attention (and eventually respect) from your DW. atm i imagine half the reason she dismisses you is because you dismiss yourself. your posts have me imagining a man who literally erases himself from his own life. if you do that to yourself, i can imagine how your wife "takes your word for it" iyswim.
not that she's not to blame, but what i'm trying to say is it's a complex "dance", this dismissiveness and disrespect. there's a chance that if you deal with your end of the bargain, she'll wake up and change things too. (chance, not certainty)
if nothing else, counselling would help you work out how you really feel. if you can't do that, it makes it harder to work out what the real issues are. as you've seen in this thread.