I can confirm this is the truth from my own experience. He accused me of cheating several times (among other forms of emotional abuse and controlling behaviour), the last time was when I said I needed space from the relationship and he messaged this whole story about how he knew I had cheated because of things I said and he had evidence etc (clearly trying to get me to rack my brain about what I could possibly have said that would have alluded to something that didn't happen), however this time round I didn't even acknowledge the accusation and didn't bother to defend myself. I just replied to say I thought it was best if we didn't have further contact.
This actually led him to retract the accusation and admit that he always knew I never had cheated and never would, but that he'd just said it because he was frustrated with me and wanted to get at me! So he'd completely made it up on the spot.
Just to give you a little insight into how their brain works.
Like quite a few men mentioned on this thread it seems, he was also ridiculously good looking, and through the entire relationship I was completely in love and smitten with him, empathised with him and wanted to save him from his demons.
Which is why it hurt so much to let him go, when I was actually still in love with him, but I was also having a nervous breakdown and panic attacks, and my head knew I literally couldn't continue it, despite my heart wanting it.
I've since been reading a book called "was it even abuse" and it's been really helpful to me. It also explains why nothing we do and say can soothe their "insecurities". It's because it's not about that.
We strive for harmony and compromise in a relationship, whereas they are not interested in that, they just strive for control. So essentially you are never on the same page and this explains why it just never seems to work despite you doing everything you think you need to do to make it work and achieve that harmony. Harmony is not their goal.