So, either my W is not "the marrying kind" or she has reached this state as a result of being M'd to me. Or, I would agree, there may be something mostly unconnected with me, that has gotten her to that point.
IMO, she's talking out of her a$s and saying these things to justify what she's telling you now/her excuses for wanting out.
And I agree with you. The question though is WHY she wants out. Just a mental exercise and a question that probably has no answer.