The relationships of Han Solo
Han initially had a rocky relationship with Leia - due to him believing that she was a spoiled princess, while Leia disliked him - due to Han being a greedy and selfish smuggler at the time. During their escape from the first Death Star, she became extremely annoyed by Han's recklessness, as he placed them at risk and almost got them captured several times. During the Battle of Yavin, however, when Vader almost succeeds in killing Luke - Han saved him - after this Leia's opinion of Han changed - and they slowly fell in love with each other. Han and Leia developed a relationship that would last throughout the war.
In The Empire Strikes, when Leia asked Han not to leave Hoth, despite the fact needed to pay off his debt to Jabba the Hutt, he he realized that she had romantic feelings for him, when he confronted Leia about this, she denied it at first. However, after they were captured by the Empire; moments before Han became frozen in carbonite, Leia realized that she loved him and admitted her romantic feelings for him, Han responds by saying; i know.
In Return of the Jedi, Leia, along with Luke, Chewbacca and Lando Calrissian go to Tatooine to rescue Han from Jabba the Hutt; their rescue mission is successful and Han and Leia lovingly embrace each other.
After Luke revealed that not only is Vader his father but hers as well, that he is her older twin brother, and left to be captured by the Empire - Han appeared to question Leia about the relationship between her and Luke, (unaware of what their conversation was about). Leia was initially unable to tell him, as she was still in shock to find out that Vader was her father and Han became jealous of Luke, but soon apologized and comforted her.
In the aftermath of the Battle of Endor, Han reassured Leia that Luke had surely survived; that he had got off the second Death Star, before it was destroyed, but she already knew it, as she felt her brother's presence though the Force. Han told her he would not interfere in their relationship, but Leia informed Han that Luke is her brother, much to his shock and and embarrassment, and they subsequently share a passionate kiss.
Sometime after the Battle of Endor, Han and Leia married and had a son named Ben. During the years of his marriage, Han found it difficult to stay in one place for long, making some aspects of his relationship with Leia difficult at times. As he was no longer a smuggler, Han spent his free time as a racing pilot during Leia's tenure as a New Republic senator. However, when their son fell to the dark side, becoming known as Kylo Ren, they separated for years in agony and grief, each mourning the loss of their son in their own way.
In The Force Awakens, after not seeing each other for many years - Han and Leia are happily reunited. Before going with Chewbacca and Finn, to rescue Rey, and destroy the Starkiller Base, Leia and Han lovingly embrace each other (unknown to either of them, this would be the last time Leia would see Han alive).
Not much is known about his relationship with his son and only child; however, Han likely had a loving relationship with his son, prior to Ben's fall to the dark side. However, Han's relationship with Ben, while loving, was flawed; Ben had abandonment issues due to the important status of both his parents and due to Han's inability to stay in one place long. This was part of the reason Ben was so easily ensnared by the First Order's ideals. Upon reuniting with Leia, Han shared his belief that there was too much of Vader in Ben to have stopped his initial struggle and fall to the dark side.
Han was devastated that his son had become evil and mourned him bitterly, yet, despite the atrocities that Ren had committed over the years - Han still believed that Ben could come back to the light and be redeemed.
Friends and Allies
At some point in his life, Han met Chewbacca, whom he saved from imprisonment. Chewbacca was so grateful for Han's intervention that he proclaimed a life debt to him; the two have been best friends since then, and Han gave him the nickname "Chewie".
Despite his loyalty to Han, Chewbacca is does not always agree with him, and often serves as Han's conscience in their smuggling endeavors. When Han died at the hands of his son Kylo Ren, Chewbacca immediately moved to injure the culprit.
Han initially had a rocky relationship with Luke - due to him believing that he was a naïve kid who needed to be taught a thing or two, while Luke disliked him due to Han being a greedy and selfish smuggler at the time. During their rescue of Leia and escape from the first Death Star, he became extremely annoyed by Han's recklessness, as he placed them at risk and almost got them captured several times. During the Battle of Yavin, however, Vader almost succeeds in killing Luke and Han saves him - after this Luke's opinion of Han changes - and they become close friends.
Sometime after the Battle of Endor, Han married Leia Skywalker, becoming Luke's brother-in-law.
Landa and Han are old friends. They breifly became enemies after Lando was blackmailed into helping Vader captue Han and his friends. They reconciled after Landa and Luke helped rescue him from Jabba the Hutt.
Rey first met Han after she and Finn barely escaped from the First Order's military forces on the planet Jakku, she was amazed to learn that who he really was; that he fought with Rebel Alliance in Galactic Civil War, and is Luke Skywalker's old friend, over time, Rey came to see Han as a mentor and father-figure, the two become good friends.
During Han's mission to rescue Rey and destroy Starkiller Base, Han is killed by Kylo Ren. Enraged by Han's death, Rey tries to kill Kylo, but the two are separated due to the planet collapsing. After this, Rey mourns and grieves over Han's death.