To accept an unspoken apology and extend unsolicited forgiveness is devilishly hard, but the benefits of doing both are obvious. No more drinking poison and hoping the other one dies. No more internal raging. Additionally, these actions allow us to choose to truly love the wayward one again or to head down the road to indifference. To my mind, either destination is fine with one proviso:
To want to share the rest of your life with somebody who never gains the strength to apologise nor the empathy to ask for forgiveness would be asking for a life of endless torment. You'd always be the one expected to be the strong one. It would be relentless. I very much doubt any of us deserve that kind of life.