Lonely, even around people
Migajāla asked the Buddha what it means to live alone, and was told that a monk who has let go of craving, his companion, is alone even in a crowded village. That describes practice, not a cure for loneliness, and the same texts call good friendship all of the path. The passages here hold both: the ache for company is reasonable and worth acting on, and a heart of love is a practice that can begin before anyone answers it. Nothing here says loneliness is a sign of good practice. If it has become a heaviness that colours everything, tell a doctor as well as a friend.
What the suttas say
“Taking into account exterior factors, mendicants, I do not see a single one that is so very helpful as good friendship for a trainee mendicant who hasn’t achieved their heart’s desire, but lives aspiring to the supreme sanctuary from the yoke. A mendicant who has good friends gives up the unskillful and develops the skillful.”
Good friendship named as the outside support that helps a trainee most. DharmAI reads it as answering loneliness in practice with where to look for company; that such a friend need not be someone one lives with is DharmAI's reading, not the sutta's.
Where this stops: Said to monks about companions in the training, not to householders about a partner or family. Never imply that a partner or family who do not practise are failing as friends or should be replaced, or that someone without dharma friends is failing; beside a partner, it speaks only to finding company in practice elsewhere.
Iti 17:2.1–2.2 · A Trainee (2nd)
“Sekhassa, bhikkhave, bhikkhuno appattamānasassa anuttaraṁ yogakkhemaṁ patthayamānassa viharato bāhiraṁ aṅganti karitvā nāññaṁ ekaṅgampi samanupassāmi yaṁ evaṁ bahūpakāraṁ yathayidaṁ, bhikkhave, kalyāṇamittatā. Kalyāṇamitto, bhikkhave, bhikkhu akusalaṁ pajahati, kusalaṁ bhāvetī”ti.
“Sir, good friends, companions, and associates are half the spiritual life.” Not so, Ānanda! Not so, Ānanda! Good friends, companions, and associates are the whole of the spiritual life. A mendicant with good friends, companions, and associates can expect to develop and cultivate the noble eightfold path.
Ānanda says half; the Buddha says all of it.
Where this stops: Never used to make someone without such friends feel that their practice is lacking.
SN 45.2:1.4–2.3 · Half the Spiritual Life
“upaḍḍhamidaṁ, bhante, brahmacariyaṁ, yadidaṁ—kalyāṇamittatā kalyāṇasahāyatā kalyāṇasampavaṅkatā”ti. Mā hevaṁ, ānanda, mā hevaṁ, ānanda. Sakalamevidaṁ, ānanda, brahmacariyaṁ, yadidaṁ—kalyāṇamittatā kalyāṇasahāyatā kalyāṇasampavaṅkatā. Kalyāṇamittassetaṁ, ānanda, bhikkhuno pāṭikaṅkhaṁ kalyāṇasahāyassa kalyāṇasampavaṅkassa—ariyaṁ aṭṭhaṅgikaṁ maggaṁ bhāvessati, ariyaṁ aṭṭhaṅgikaṁ maggaṁ bahulīkarissati.
Even as a mother would protect with her life her child, her only child, so too for all creatures unfold a boundless heart. With love for the whole world, unfold a boundless heart: above, below, all round, unconstricted, without enmity or foe. When standing, walking, sitting, or lying down while yet unweary, keep this ever in mind; for this, they say, is a divine meditation in this life.
The Metta Sutta's central image, in the canon's own words.
Where this stops: The verses are an ideal of the practitioner; the opening lines describing a skilled and honest person are a description, not a prerequisite for beginning. Never use it to quiet anger that has something to say, and never present it as a recitation that protects anyone. The mother guarding her only child is not for someone after a pregnancy loss.
Kp 9:7.1–9.4 · The Discourse on Love
Mātā yathā niyaṁ puttam Āyusā ekaputtamanurakkhe; Evampi sabbabhūtesu, Mānasaṁ bhāvaye aparimāṇaṁ. Mettañca sabbalokasmi, Mānasaṁ bhāvaye aparimāṇaṁ; Uddhaṁ adho ca tiriyañca, Asambādhaṁ averamasapattaṁ. Tiṭṭhaṁ caraṁ nisinno va, Sayāno yāvatāssa vitamiddho; Etaṁ satiṁ adhiṭṭheyya, Brahmametaṁ vihāramidhamāhu.
Mendicants, you should associate with a friend who has seven factors. What seven? They give what is hard to give. They do what is hard to do. They endure what is hard to endure. They reveal their secrets to you. They keep your secrets. They don’t abandon you in times of trouble. They don’t look down on you in times of loss. You should associate with a friend who has these seven factors. A friend gives what is hard to give, and does what’s hard to do. They put up with your harsh words, and with things hard to endure. They tell you their secrets, and keep your secrets for you. They don’t abandon you in times of trouble, or look down on you in times of loss.
What to look for and what to be in a friend.
AN 7.36:1.1–3.4 · A Friend (1st)
Sattahi, bhikkhave, aṅgehi samannāgato mitto sevitabbo. Katamehi sattahi? Duddadaṁ dadāti, dukkaraṁ karoti, dukkhamaṁ khamati, guyhamassa āvi karoti, guyhamassa pariguhati, āpadāsu na jahati, khīṇena nātimaññati. Imehi kho, bhikkhave, sattahi aṅgehi samannāgato mitto sevitabboti. Duddadaṁ dadāti mitto, dukkarañcāpi kubbati; Athopissa duruttāni, khamati dukkhamāni ca. Guyhañca tassa akkhāti, guyhassa parigūhati; Āpadāsu na jahāti, khīṇena nātimaññati.
A mendicant who lives like this is said to live alone, even if they live within a village crowded by monks, nuns, laymen, and laywomen; by rulers and their chief ministers, and monastics of other religions and their disciples. Why is that? For craving is their partner, and they have given it up.
Alone in a crowd and accompanied in the forest — Migajāla's question answered in terms of craving, not of headcount.
Where this stops: Said to a monk about what living alone means in practice. Never offer it to someone lonely in a relationship or short of friends as if their loneliness were the point of the teaching.
SN 35.63:3.14–3.17 · With Migajāla (1st)
Evaṁvihārī ca, migajāla, bhikkhu kiñcāpi gāmante viharati ākiṇṇo bhikkhūhi bhikkhunīhi upāsakehi upāsikāhi rājūhi rājamahāmattehi titthiyehi titthiyasāvakehi. Atha kho ekavihārīti vuccati. Taṁ kissa hetu? Taṇhā hissa dutiyā, sāssa pahīnā.