Self-love means giving yourself what you want others to give you
What “You can’t love others if you can’t love yourself” really means is that if you are missing fundamental self-love, you will end up becoming fearful, controlling, and codependent in relationships because you are dependent on a source of love you have no control over. And that’s a fundamentally untenable position. It doesn’t mean you don’t love or care for other people. It just means eventually your love will turn into some form of controlling behavior that is not really based in love but in fear of losing love.
Self-love is not an abstract concept. It just means being OK being who you are, and not needing someone else’s permission to approve of yourself or take care of your own needs. And it’s the basis of healthy relating because if you can give yourself love, you won’t compromise your needs to attain love from others, and therefore you won’t become resentful or overwhelmed in relationships.
But if you were not loved as a child, you have to learn how to love yourself. Which takes quite a lot of work and time. But it helps if you stop thinking of it as a nebulous, abstract concept or purely based on feelings. Think of it as learning how to take care of a hamster, but more complicated. Imagine giving that hamster everything it needs to be a happy hamster. That is how you love a hamster. You love yourself the same way. You make sure you have what you need to thrive. You stop depriving yourself, thinking it will earn you love. You stop punishing yourself, thinking it will redeem you. You let yourself pursue what makes you uniquely happy, regardless of what people think of it. You stop putting off loving yourself until someone else loves you. You let go of the past and let yourself just exist as a person in the here and now, doing the best you can. Nothing to prove, nothing to earn, and nowhere else to be but the present moment.