That sounds really hard. I don't know your situation, but I do know of a few cases where somebody felt this way about their SO and were able to rekindle their relationship through couples therapy. You mentioned that you haven't been outright with your feelings, and that your spouse doesn't seem to understand them. It's good to have separation on the table, and accept that it might be necessary, but it sounds to me like you haven't really tried to work through things with your spouse yet. I don't think that's fair to either of you.

I'm not saying you haven't done anything, but I question your commitment to change when you seem more ready to talk about separating than to talk about working through things. That doesn't sound entirely like the fault of your spouse. Are you having second thoughts about settling down?