What does the Gita say about relationships?
The Bhagavad-Gita talks about relationships in two contexts. Our current existence is multilevel. We are eternal souls but are material bodies residing. So we have relationships at the material, bodily level with others and, while we are in the body, those relationships are important.
As according to Lord Krishna: If a man loves a woman and if a woman loves a man, but families are against their love and marriage, then it is called as Dharma if both man and woman run away with each other and spend their lives peacefully somewhere else after getting married.
I am the same to all beings, and my love is ever the same; but those who worship me with devotion, they are in me and I am in them. For if even one who does evil were to worship me with all his soul, he must be considered righteous, because of his righteous will.
“To love without condition, to talk without intention, to give without reason, care without expectation, that's the spirit of true love.”
The Bhagavad Gita does not say anything specific about divorce. The Bhagavad Gita speaks about the importance of marriage, but not about divorce.
Mahabharata depicts the desire to love and be loved as the basic instinct of almost all major characters. This love includes all the three dimensions of sexual, emotional and spiritual gratification.
According to another belief, Radha represented Jeevatma while Shri Krishna is the Paramatma. Radha's selfless love was the highest form of devotion. And therefore, she merged into Shri Krishna by surrendering herself. Hence, since she had united with him, there arose no need for marriage.
They meet each other of their own accord, consent to live together, and their relationship is consummated in copulation born of passion. This form of marriage did not require consent of parents or anyone else. According to Vedic texts, this is one of earliest and common forms of marriage in Rig Vedic times.
Every Hindu must marry. “To be mothers were woman created and to be fathers men.” The Veda ordains that “Dharma must be practiced by man together with his wife and offspring”.
Lord Sri Krishna says this:
Women during their rajaswala (menstrual period) are not supposed to perform any work pertaining to the household / family works. Invariably, those women need to take rest for the all the four days of rajaswala (menstrual period).
What is greatest sin according to Gita?
In this Geeta, Rama has given due importance also about the greatest sin. According to Rama the greatest sin is to snatch or cheat the subsistence source of anybody, especially those whose life is based on honest deeds and earnings.
Yes, true love exists, but it's not nearly as common as people like to think it is. Love doesn't always equal compatibility, nor does it mean that people are meant to stay together for a lifetime.

In verse 18 of Bhagavad Gita, it is written in verse 39 that when the raga increases a lot, then this raga takes the form of Tamo guna, which is called attachment, and because of this fascination, the man likes to sleep more, the more sleep one too much sleep is not good and deep sleep, because of not getting enough ...
Essentially, true love means that you have an unwavering, unbreakable and unparalleled fondness and devotion for your partner. It's also defined by an emotional as well as physical connection with him or her that runs immeasurably deep, and life without your significant other would be practically unthinkable.
In his Gita Govinda Krishna speaks to Radha: O woman with desire, place on this patch of flower-strewn floor your lotus foot, And let your foot through beauty win, To me who am the Lord of All, O be attached, now always yours.
In case, you hurt others that is very small in magnitude, go voluntarily and beg his pardon. If he forgives you, you can get relieved from that small offence. However, very big actions that have ruined the life of a person can not be just pardoned with words and hence he has to face the reactions in future.
So, to summarize, it does NOT mean "having nothing to do with the family." Rather, the family should be a source of spiritual strength and support. If it becomes a detriment to spiritual life then one should be detached enough to see it in the proper light.
The Bhagavad-Gita when Krishna is speaking to Arjuna He takes more or less like a parental role, the role of a Guru is parental. Just a parent gives guidance, the Guru gives guidance. But even while and Arjuna also accepts this that you are like a father forgives the son, You please forgive me.
Do your duty, but do not concern yourself with the results. We have the right to do our duty, but the results are not dependent only upon our efforts.