Sometimes a person is unlovable not because of the way they are, but because their concept of love is so warped that it severs them from love entirely. Arthur may crave love, but he would flinch away from it if he were to get it, or become so consumed by it that the experience would make him sick. To him, love has always been smothering, brutal, and clawing; like having his head held underwater. His mind endlessly sieves through it, but his body will never let him accept it.
The unlovable person has value as they are, but that value is not readily seen. Often, their value is actively denied. When the unlovable person is discussed it is with suspicion, pity, or disdain, because the unlovable person is alone, and the lonely are despised. So there is a demand - framed as a moral imperative - for the unlovable to reform themselves. This focus harms the unlovable by miring their existence in tragedy and destruction. It impedes the change demanded of them.
Acceptance of one's unlovability is disturbing to many. It is akin to accepting inhumanity. But to the unlovable person this acceptance does not necessarily mean a rejection of others - it is peace with oneself. To say "I am unlovable" is not synonymous with "I am discardable, I am nothing, I am without value," it is comfort with what is true in the moment. And because all moments end, it can also be a stepping stone to something new. What lies beyond love, or beside it? Only the unlovable person can seek this out. And what they are able to find - this thing so unique to them - is part of their inherent worth.