Apart from an inbuilt and innate need for intimate relationships, human beings also have an inbuilt and innate need for attachment to another person, to improve their security when this is threatened. The latter is the heart of John Bowlby's attachment theory. Some people seem to use the word attachment as a novel and somewhat dusted-off variation on love, but this is not how attachment has been used in attachment theory for almost 50 years.
It is important to distinguish between the need for intimate relationships, meaning equal, mutual, intimate relationships, and the need for attachment security, which is one-sided and unequal (but not exploitative), and where one person needs the security, and the other is the caregiver. These differences are complex but fundamental.
Some of the apparent confusion may be caused by the fact that human beings need both security and intimate relationships. However, that is not an excuse for confusing the two, or suggesting that they really are the same thing.
Implications for adult intimate relationships
For adults it is possible to combine the two, i.e. the people with whom you have your main intimate relationships may, and are likely to be there for you, when you are afraid, in need of care, and seek security. However, this is a limited and subsidiary element of what an adult intimate relationship is about. An adult intimate relationship is built on equality and mutuality. An intimate relationship that is mainly about one person getting their attachment or security needs met, is probably so unequal as not to be a full adult intimate relationship.
When you are in an intimate relationship, it may help that relationship if the partners are aware of and able to talk about the role that their need and search for attachment security plays in the relationship.