What does the Gita say about marriage?

बलं बलवतां चाहं कामरागविवर्जितम् ।
धर्माविरुद्धो भूतेषु कामोऽस्मि भरतर्षभ ॥

balaṃ balavatāṃ cāhaṃ kāma-rāga-vivarjitam
dharmāviruddho bhūteṣu kāmo 'smi bharatarṣabha

I am also the strength of the strong, unaccompanied by fondness or desire. And, O chief of the descendants of Bharata, I am love unopposed to piety among all beings.

युक्ताहारविहारस्य युक्तचेष्टस्य कर्मसु ।
युक्तस्वप्नावबोधस्य योगो भवति दुःखहा ॥

yuktāhāra-vihārasya yukta-ceṣṭasya karmasu
yukta-svapnāvabodhasya yogo bhavati duḥkhahā

For the one who eats and exercises moderately, who works moderately, and who sleeps and wakes at proper times, that yoga destroys all suffering.

तेजः क्षमा धृतिः शौचमद्रोहो नातिमानिता ।
भवन्ति संपदं दैवीमभिजातस्य भारत ॥

tejaḥ kṣamā dhṛtiḥ śaucam adroho nātimānitā
bhavanti saṃpadaṃ daivīm abhijātasya bhārata

…nobility, forgiveness, courage, purity, freedom from malice, and absence of vanity—these, O descendant of Bharata, belong to one born with divine qualities.

असक्तिरनभिष्वङ्गः पुत्रदारगृहादिषु ।
नित्यं च समचित्तत्वमिष्टानिष्टोपपत्तिषु ॥

asaktir anabhiṣvaṅgaḥ putra-dāra-gṛhādiṣu
nityaṃ ca sama-cittatvam iṣṭāniṣṭopapattiṣu

…absence of attachment, absence of self-identifying regard for son, wife, home, and so forth; and constant equability on the approach of both what is agreeable and what is disagreeable…