What do the Stoics say about love and heartbreak?

Epictetus does not tell you to love less. He tells you to love with your eyes open. In the Handbook he gives the example of kissing your child or your wife: say that you only kiss things which are human, and thus you will not be disturbed if either of them dies (Handbook 3). The instruction is not to withhold affection. It is to remember, in the moment of affection, what kind of thing you are holding: a mortal being, not a possession you control.

The common misreading is that Stoicism wants you to armor yourself against love so that loss cannot touch you. That would make heartbreak a problem to be engineered away, and the Stoic a person who loves less in order to hurt less. But look at what Epictetus actually recommends in the Discourses. He describes kissing your child and saying, in a lisping voice, tomorrow you will die, and saying the same to a friend: tomorrow you will go away or I shall, and never shall we see one another again (Discourses 3.24). He knows this sounds like an ill omen, and he answers the objection directly: he does not care whether the words sound ominous, only whether they are useful (Discourses 3.24). The point of rehearsing loss is not to feel loss in advance so love hurts less now. It is to keep clear, while you love, that the person is not yours to keep. That clarity is what changes how heartbreak lands when it comes.

This is why the Stoic position is not the "insensible soul" that Seneca discusses in his letter on friendship. Seneca reports the debate between Epicurus and Stilbo over whether the wise person needs friendship at all, since some held that the highest good was a soul insensible to feeling (Moral Letters 9.1). Seneca is careful about the Greek word usually translated as this insensibility, apatheia, because the Latin rendering, impatientia, can be misheard as a soul that cannot endure any evil, when the Stoics mean the opposite: a soul that rejects any sensation of evil, one entirely beyond the reach of harm (Moral Letters 9.2). He proposes better renderings: a soul that cannot be harmed, a soul beyond the realm of suffering (Moral Letters 9.2). That is a claim about what can damage your character, not a claim that you should feel nothing when someone you love leaves or dies.

Put these together and the shape of the Stoic view comes into focus. You are permitted, even expected, to love other people fully. What is not permitted, on the Stoic account, is placing your good in something you do not control, since only your own judgments, desires, and choices are up to you. A partner's affection, a friend's presence, another person's choice to stay: none of that is up to you. So heartbreak, on this view, is real grief at a real loss, but it need not become the belief that your life has been ruined, because your character and your capacity to act well were never in that other person's hands to begin with.

What changes in practice is not how much you love but what you attach your sense of self to. Epictetus's exercise, remembering as you kiss your child that you kiss a human being, asks you to hold the relationship and its impermanence at the same time, rather than pretending the second fact away until it arrives as a shock. Applied to heartbreak: before it happens, notice plainly that the person you love is a mortal, free being who owes you nothing and can leave. When it does happen, the grief is not a sign you did something wrong. The question worth asking afterward is whether you are still the same person, capable of acting well, of loving again, and of judging the loss for what it is rather than for what your fear made of it in advance.