It took me 2 years to become as completely comfortable with my choice as I ever got (99.99999%), but my W was consistently remorseful in her behavior from d-day on. Later she told me and our MC that she didn't feel remorseful for at least 5 months, but she consistently did remorseful things from d-day on.
If you're going to R, IMO you need to respond to the here and now. You say your WS is behaving the way you want him to behave, right? If he keeps doing that, you really need to take it in. You are also feeling anger and mistrust in the here and now. That's important, and I suggest you talk about that with someone, a good IC if you can find one.
You describe the thoughts and feelings of someone in incomplete R, which is great for someone who's only 20 months out, because the SI rule of thumb is 2-5 years to recover.
Stay loose. The last chapter hasn't been written yet. Your WS may continue as a great candidate for R. OTOH, it's possible that he's just acting now; if so, that will come out, probably in the next year. If he bcoems the lousy H again, you'll know what to do.
fBH (me) - on d-day: 66, Married 43, together 45, same sex ap
d-day - 12/22/2010 Recover'd and R'ed
You don't have to like your boundaries. You just have to set and enforce them.