Humans might use a nuanced concoction of chemicals even more complex than formal pheromones to attract potential mates. Sometimes people can't help but be attracted to other people due to the chemical make up of their bodies. For example even though Tom does love Daisy, he can't help but be attracted to Myrtle due to her complexion. Daisy is smaller and more dainty, while Myrtle is a more well rounded individual. The temptation that Tom feels for her overcomes him and his love for Daisy, causing him to be disloyal to Daisy.
There is a difference between Love and obsession and you see an example of both in this novel. According to this article, healthy obsession is fine but when it reaches a catastrophic point it can be quite damaging. Although Gatsby is a nice young gentleman, he does demonstrate symptoms of obsessive love. He is so obsessed with Daisy to the point where he stalks her every move, buys a house so he can be close to her, and throws excessive parties just in hope she may just walk in. Even though he truly loves her, he loves her to an extent that is quite unhealthy and eventually causes him to pay the price for it.
According to this article there are 3 forces that influence your decision making process. The id, ego, and super ego. Sigmund Freud said that these forces influence people and why they are tempted to sometimes to the wrong thing even if they understand right from wrong. For example in the book after Daisy runs Myrtle over she has the chance to go back and tell everyone what she has just done, but she listens to her Id and in turn Gatsby is then blamed for all this. She could have done the right thing, but she is tempted by her Id to take the easy way out so she won't receive any blame even if Gatsby is harmed by all this negativity. An example of the superego being used from this is how Gatsby never blames Daisy for what she did and how she was the one that killed myrtle. Instead of being tempted by his Id, he listens to his superego and Daisy's reputation and life are saved from the likely downfall that would have came from this.
Temptation is a person's ability to choose either good or evil. In this novel there are a lot of occasions where people can do the right thing but are tempted to do the wrong thing. For example when Daisy and Gatsby are falling in love once again, instead of telling Tom so Daisy can leave him right away she is tempted to break his heart in the way he has been doing to her. Daisy knows that Tom suspects of them, but instead continues to make it more and more obvious so Tom knows and feels the way she has felt on countless occasions. Instead of listening to her good side she is tempted to do this to Tom and it ultimately leads to the downfall of her love for Gatsby.
This song is a great example of all the characters feelings about love throughout the novel. The songs lyrics are about how this man has been hurt by his lover after she has lied to him, cheated, and left him. All the main characters from the novel have suffered their fair share of heartbreaks due to the carelessness of a lover. Tom was heartbroken when Daisy chose Gatsby, Daisy was heartbroken when Tom cheated on her, Gatsby was heartbroken when Daisy wouldn't admit that she never loved Tom. Even Nick is rather heartbroken to learn that Jordan is just like the rest of the girls. The main lyrics of this say, "baby don't hurt me, don't hurt me, no more", which really applies since they have all been hurt. The title of the song also applies since no one in the novel truly knows what love is.
According to this article there are 3 different brain functions that affect a person when they feel the presence of love. First off, we have the sex drive/lust which is very eminent in the novel. For example how even though Tom does love Daisy in his own way he is driven by a deeper force inside him that causes him to take whatever he thinks he deserves, even causing him to cheat on Daisy. Secondly we have the romantic desire/infatuation, which is also present in the novel. This is demonstrated by Gatsby multiple times throughout the book, since the love he feels for Daisy is purely emotional and out of attraction rather than lust like that of Toms. The last thing is attachment through time, which we see through Daisy and what she feels for Tom. Even though deep down she does not truly love Tom, she is fickle and weak minded and in a way is attached with Tom because of the time they have been together. They have a kid and many memories together, she loves what he stands for, but not him as a person. Although Tom and daisy do love each other they can't seem to stay true due to the fact that have too many outside temptations guiding their judgment.