"Being deeply loved by someone gives you strength, while loving someone deeply gives you courage." - Lao Tzu
When I was a teenager I read something by Tolkien that has always stayed with me: that the heady romantic love people feel at first turns into a another kind of companionate, long-lasting love. That has been my experience, too.
The Greeks, who thought about everything, and were smarter than we are, noticed there at least four kinds of love: Agápe, Éros Philia and Storge.
I'll just quote from Wikipedia:
"Agápe means love in a 'spiritual' sense. In the term s'agapo (Σ'αγαπώ), which means "I love you" in Ancient Greek, it often refers to a general affection or deeper sense of 'true unconditional love' rather than the attraction suggested by 'eros.; This love is selfless; it gives and expects nothing in return. Agape is used in the biblical passage known as the 'love chapter,' 1 Corinthians 13, and is described there and throughout the New Testament as sacrificial and spiritual love. Whether the love given is returned or not, the person continues to love (even without any self-benefit). Agape is also used in ancient texts to denote feelings for one's children and the feelings for a spouse, and it was also used to refer to a love feast. It can also be described as the feeling of being content or holding one in high regard. Agape was used by Christians to express the unconditional love of God.
"Éros (ἔρως érōs is 'physical' passionate love, with sensual desire and longing. Romantic, pure emotion without the balance of logic. 'Love at first sight'. The Modern Greek word 'erotas' means 'intimate love;' however, eros does not have to be sexual in nature. Eros can be interpreted as a love for someone whom you love more than the philia, love of friendship. It can also apply to dating relationships as well as marriage. Plato refined his own definition: Although eros is initially felt for a person, with contemplation it becomes an appreciation of the beauty within that person, or even becomes appreciation of beauty itself. Plato does not talk of physical attraction as a necessary part of love, hence the use of the word platonic to mean, 'without physical attraction.' In the Symposium, the most famous ancient work on the subject, Plato has Socrates argue that eros helps the soul recall knowledge of beauty, and contributes to an understanding of spiritual truth, the ideal 'Form' of youthful beauty that leads us humans to feel erotic desire – thus suggesting that even that sensually based love aspires to the non-corporeal, spiritual plane of existence; that is, finding its truth, just like finding any truth, leads to transcendence. Lovers and philosophers are all inspired to seek truth through the means of eros.
"Philia (φιλία philía) is 'mental' love. It means affectionate regard or friendship in both ancient and modern Greek. This type of love has give and take. It is a dispassionate virtuous love, a concept developed by Aristotle. It includes loyalty to friends, family, and community, and requires virtue, equality and familiarity. In ancient texts, philos denoted a general type of love, used for love between family, between friends, a desire or enjoyment of an activity, as well as between lovers.
"Storge (στοργή storgē) means 'affection' in ancient and modern Greek. It is natural affection, like that felt by parents for offspring. Rarely used in ancient works, and then almost exclusively as a descriptor of relationships within the family. It is also known to express mere acceptance or putting up with situations, as in 'loving' the tyrant.
C.S. Lewis wrote a famous book called The Four Loves, in which he described the four loves this way:
Storge – affection
Philia – friendship
Eros – romance
Agape – unconditional love
Lewis also came to the conclusion there is element in love not much discussed today: Appreciative love. This is why I point out in true love there is always appreciation and gratitude.
Lewis had this to say about the perversion of Eros: "[he] warned against the modern tendency for Eros to become a god to people who fully submit themselves to it, a justification for selfishness, even a phallic religion."
Again I will quote Meister Eckhart: "If the only prayer you ever say in your entire life is thank you, it will be enough."
That's been my experience, too: in true love there is always appreciation and gratitude. If you can't feel that, then you are in a sorry way.