I'd say that while it's normal to long for an apology, if you really need it, you're not ready to speak to whoever harmed you. Non-apologizers tend to walk on a tightrope of defensiveness above a huge canyon of low self-esteem - they just can't listen to anything that's going to set them off balance. So focus on what you say for your own sake, because you need to hear your own voice telling the truth.
Request an apology when you believe you deserve one, but don't get in a tug of war about it. Instead, be a role model and tender a genuine apology yourself when an apology is due. Your willingness to apologize can be contagious and models maturity for your partner. Also, your non-apologizing partner may use a nonverbal way to reconnect after a fight, defuse the tension, or show you he's in a new place and wants to repair a disconnection. Accept the olive branch however it's offered.
The best apology, I think, was from my husband, Steve, who slept with a close friend of mine decades back, when we were committed to being life partners but not yet married. And many of the factors that made Steve's apology so healing are universal. One important thing is that he confessed to the affair, rather than my discovering it. He looked deeply into his own history in terms of why this happened, but he never used that history as an excuse.
There are some things for which there is no apology, and on the question of slavery, there is no adequate apology for ripping people out of their homeland and bringing them here in chains. There is no adequate apology for the ongoing horrific legacy of racism.
It's true that over-apologizing interrupts the flow of conversation and irritates the person who has to stop and offer reassurance, like, "No, it's fine, don't worry about it." But far greater than the challenge of toning down unnecessary "sorrys" is offering an apology when one is due.
