Just to add my thoughts in to the mix "OhFor".
I would say that acceptance is "a" way, not necessarily "the" way. If it's put to you as an absolute then that puts pressure on you to make certain choices. But nobody else has lived your life. Only you know what you can accept and what you can forgive.
Also what does acceptance mean in this context? Is it a realisation, or a coming to terms, or saying that something is ok. I accept the fact of what my ex has done. I can accept some of the reasons as to why he may have acted as he did. But can I honestly say I accept it, as the actions of a flawed human being, just as I am flawed?
I think it may be possible to accept but not to forgive. I've reached a certain level of acceptance by looking at things logically. The motives of him, and others, I accept I'll never understand. This gives me a certain peace because I'm no longer looking for answers.
Holding onto the anger can be very corrosive. I choose anger some days over sadness because it gives me more energy, more motivation. But ultimately it makes me feel worse. I wrote to my ex some months ago to say I didn't hold grudges, just wanted the best for us all, and hoped in the future we could try and parent together. He never even acknowledged it. I didn't feel angry, just sad.
I personally don't feel the need to forgive. What's done is done. What I have observed him and others do is unforgiveable - by me at least. I don't think this is me holding on to my anger. For me it's a form of acceptance. You have done this thing to me, I will not say it's ok, but I choose to move on.
I saw an interview once with the bereaved parent of a child. It's an infamous case. The parent was consumed with hatred and rage, and it was destroying his life. The interviewer (a monk) asked him what would happen if he let go of his anger. The man became distraught. He thought about it and said it meant he was letting his child down. He needed the anger to carry on.
I know we're talking about a different situation, but I wonder if we can't/don't accept and/or forgive because of what that would mean for us? I don't think accepting something means it was ok. I think it means you know it wasn't ok, but you can look it straight in the eye, see it clearly, and move away from it. No excuses, no reframing, just maybe a cold, hard acceptance.