I think what you are explaining is normal and to be expected. Moreover, the fact that you have made it three years in and can say you feel "OK-ish" 90% of the time WITHOUT having been to IC/MC...that is virtually a miracle.
That said, knowing what I have learned so far you really should consider (at least) going to IC or MC. You don't have to do carry what you are carrying alone or without help. I do not know the full picture of your "case" - but I view everyone's situation like this - you took a lot of emotional hits and suffered a lot of emotional hurt and damage (I'm guessing). You have to PUT that somewhere healthy. If you cram it into a safe and swallow it you can be certain that it will leak out slowly over time in unhealthy ways...anger...resentment....depression...and so on. I am guessing that would explain the "ish" in "90-ish" and for sure explain the 10% of the time when you are not doing well.
If your H is remorseful on some level and appears to be all-in for your relationship, don't be afraid to say you need that kind of help. Be brave.
