To be the recipient of an apology

Lately I've been working hard to become even more conscious of my thoughts and actions. Although I'm usually very tuned into myself in what I say and do and think throughout the day, I've come to realize that I am still often on autopilot, saying and doing things without even thinking twice about it. Sometimes, after I say or do something, I reflect on the moment and am astonished at how uncharacteristic my words and actions can be. And moreso, how contrary they sometimes are to how I actually feel about a particular event, person, or situation.

In thinking some of these instances through, I've discovered that I'm struggling with one situation in particular. I've realized that when someone approaches me with an apology, my first reaction usually is to say, "It's ok." However, sometimes, it's NOT ok! Sometimes, I have been hurt and an apology is definitely warranted! Sometimes, the actions towards me are inexcusable and at minimum, an apology is the first step in resolving the matter and restoring the relationship. Despite knowing all this, my default response is "It's ok?!" What's up with that?! I might as well say:
It's ok that you hurt me.
It's no big deal.
You don't need to take responsibility for your actions.
I am not worthy of receiving your acknowledgement for what happened.
It is acceptable to do/say what you did/said again.
It's ok that you hurt me.

Although I might have been a bit dramatic in the progression above, no matter how you look at it, the simple, "It's ok" is literally telling the other person that it's tolerable to hurt me, tolerable to break their agreement with me, tolerable to be less than their best with me, etc. Why do I, a self-assured, strong, responsible, aware woman of integrity and great worth automatically grant such permission?! Why do I find it so difficult to accept the apology verbally and then move on?

I once had difficulty accepting compliments and at one point in my journey of personal growth, I participated in a coaching program. My coach learned about my struggle and saw that it was contributing to my view of self and my confidence level in all areas of life. In order to support me in changing that view, he encouraged me to say "Thank you, it's true" after each compliment that was given to me. Not to be arrogant, however to genuinely accept the gift of the compliment (who am I to deny that from the person who wants to share it?) and to acknowledge the truth behind their words. (I am great at what I do. I am beautiful. This shirt does look good on me. I really am wonderfully thoughtful. I do have a great smile. I am brilliant and loveable and sexy . . .) After awhile, accepting compliments was not as difficult as it used to be and more importantly, I began to believe, really believe, the positive things others were telling me. I still occasionally do catch myself rejecting compliments from others, however I usually catch myself in those moments and am able to make a different choice in how I respond to the compliment and by doing so, I am able to make a different choice in telling myself who and how I am.

Ok, so as I reflect upon that experience, I am still attempting to figure out the "why" behind some of my actions, and I am still stuck on what the truly appropriate response is to "I'm sorry," or "I apologize." I mean, in the past I've said "Thank you for your apology," or "I appreciate that," or the no-longer-adequate "it's ok." But truly, honestly, what is a good response? How can I accept the apology without diminishing it or dismissing the circumstance(s) which called it forth? Please know I am not speaking of forgiveness (I don't find that very difficult at all in most cases), however I'm speaking of my verbal acknowledgment of the apology and what that reiterates to my being in regards to what happened and how I feel in a particular situation. Therefore, what can I say that more appropriately expresses how I am feeling in that moment in time?