There are scarcely any who are not ashamed of having loved, when they love no longer.

[Il n’y a guère de gens qui ne soient honteux de s’être aimés quand ils ne s’aiment plus.]

François VI, duc de La Rochefoucauld (1613-1680) French epigrammatist, memoirist, noble

Réflexions ou sentences et maximes morales [Reflections; or Sentences and Moral Maxims], ¶71 (1665-1678) [tr. Stevens (1939)]
    (Source)

First appeared in the fifth (1678) edition.

(Source (French)). Alternate translations:

There are few people who are not ashamed of their amours when the fit is over.
[pub. Donaldson (1783), ¶271; ed. Lepoittevin-Lacroix (1797), ¶69]

Most people are ashamed of their amours when the fit is over.
[ed. Carville (1835), ¶232]

There are very few people who, when their love is over, are not ashamed of having been in love.
[ed. Gowens (1851), ¶181]

There are few people who would not be ashamed of being beloved when they love no longer.
[tr. Bund/Friswell (1871)]

There are few of us who are not ashamed of a mutual passion when love has died.
[tr. Heard (1917), ¶177]

When two people have ceased to love, the memory that remains is almost always one of shame.
[tr. FitzGibbon (1957)]

Few people, when they love no longer, but feel shame for having loved.
[tr. Kronenberger (1959)]

There are few people who, when their love for each other is dead, are not ashamed of that love.
[tr. Tancock (1959)]

There are few people who are not ashamed of having loved each other when they no longer do so.
[tr. Whichello (2016)]