Relationships of Happy Hogan in the Marvel Cinematic Universe.
Romance[]
May Parker[]

In Spider-Man: Far From Home, Happy and aunt May have an unofficial, flirtatious relationship, much to Peter's dismay. Whilst Peter is away in Europe, Happy helps May in her charity work that evolves around those who were displaced by the blip. When Happy travels to London to save Peter's friends - MJ, Betty, Ned and Flash - Happy says he is in love with May when they all think they are going to die, much to everyone's confusion. Back in the US, Peter asks May and Happy if they are dating, Happy says yes whilst May says no, causing the two to have a discussion about it and Peter leaves for his date with MJ, feeling awkward.
In Spider-Man: No Way Home, minutes after Peter Parker's identity as Spider-Man has been revealed to the world, May and Happy are in her apartment, breaking up. May lets Happy down easy saying their short-lived romance was fun but was a fling, not a real relationship. Happy tries to get May to reconsider when they hear Peter and his girlfriend Michelle Jones enter through his window. May tries to get Happy to leave once they think the teenagers are about to get intermate.
Despite their split, Happy and May help Peter speak with Matt Murdock who is acting as the young avenger's lawyer for the case against Mysterio. May tries to get Happy to relax once he starts to panic when Matt tells him he will need a really good lawyer for working with Stark Industries. When May and Peter realise they need a safer place to live, Happy allows them to stay with him in his highly security condo.
Happy later returns to his apartment complex to find May has died from Green Goblin's attacks, there, and is devastated upon seeing Peter crying over his aunt's corpse. However, Happy has no time to mourn as he is arrested by Damage Control and tells Peter to flee quickly. After Spider-Man asks Doctor Strange to cast a spell for the world to forget who Peter Parker is, Happy is seen mourning at May's grave with Peter, not knowing who this young man is. Once the teenager leaves, Happy stays behind for a while to mourn May.
Friends and Allies[]
Iron Man/Tony Stark[]

Tony and Happy in Iron Man 2
Tony and Happy have been friends and employee/employer since the 90's. The two are extremely close friends. They are sometimes seen boxing together or just hanging out even though Happy works for Tony. Happy is often seen being Tony's scoffer most of the time as seen in various movies, and Happy also sometimes has Tony's Iron Man armor for whenever he needs it.
In Iron Man 2, Tony promotes Happy to security, which he takes very seriously and even when Happy temporally stops working for Tony, they are still extremely close and Happy often gives Tony advice.
Happy has kept the engagement ring for Tony to give to Pepper since 2008 for whenever he wanted to give it to her. In a deleted scene from Avengers: Infinity War, Happy is determined to keep Tony and Pepper's wedding news out of the tabloids and Tony advises. Tony even suggests to Pepper to get Happy a girlfriend.
Happy attends Tony's funereal in Avengers: Endgame, where he morns the loss of his boss and is close with his daughter Morgan.
Pepper Potts[]

Happy and Pepper in Iron Man
Happy and Pepper have been close friends ever since she was hired to work for Tony Stark. When Tony returns from captivity in Afghanistan, Pepper asks Happy to take Tony to the hospital which he agrees on although Tony, not so much.
In Iron Man 3, Pepper congratulates Happy's promotion to Head of Security and they work together with Pepper now being the CEO of Stark Industries. Happy keeps tabs on Pepper to make sure she is safe.
In a deleted scene from Avengers: Infinity War, Happy does whatever he can to keep the upcoming wedding of Pepper and Tony out of the tabloids. Happy then comforts Pepper and her daughter Morgan after Tony's death in Avengers: Endgame.
Peter Parker/Spider-Man[]

Happy and Peter in Spider-Man: Far From Home
Happy first meets Peter Parker in Captain America: Civil War to travel to Germany after Tony Stark finds out that Peter is the new superhero known as Spider-Man.
In Spider-Man: Homecoming, Peter has footage of him and Happy travelling to Germany and Peter is excited when he realises his and Happy's rooms are next to each other. Happy, however, has to knock on Peter's door to ask him to keep the sound volume down saying there are thin walls in the hotel. Happy has to keep an eye on Peter throughout Homecoming as rules by Tony.
In 2024, after being resurrected by the Hulk, Happy serves as a support system for Peter when he is struggling with the loss of Iron Man months after his death. Peter calls Happy for help and a ride when he is stranded in Holland, but is scared to see him at first as he believes Happy is another one of Mysterio's illusions (after seeing both MJ and Iron Man in illusions). Happy mentions to Peter about their time 8 years ago when they went to Germany together and Peter hugs Happy, feeling relieved that he is the real Happy and not another illusion.

Happy and Peter in Spider-Man: No Way Home
Happy helps stitch Peter up after his hit with an upcoming bullet train back in Holland and Peter explains his feelings to Happy, who tells Peter that he may never be Iron Man, but he doesn't need to be, he just needs to be his own hero. Peter, whilst designing his suit, gives Happy the necklace he wants to give MJ in case he might not make it back, but Happy assures him he will, but Happy does eventually give MJ the necklace.
Happy helps Peter, as Spider-Man, travel to London to defeat Mysterio by flying him there and Happy goes to rescue his friends MJ, Ned, Betty and Flash from Mysterio's attacks.
In Spider-Man: No Way Home, Happy would later help shelter Peter and his aunt May at his highly secure apartment after the former's identity was revealed and he was framed for Mysterio's murder. Happy told Peter to flee as DODC started firing at the hero who was morning his deceased aunt. Peter fled while Happy was arrested and noticed May dead on the ground outside the apartment building. Following Happy's memory being wiped by a spell, he went back to not knowing who Peter was like the rest of the world. The two later bumped into each other in December when they both visited May Parker's grave. The two mourned together and Happy, not knowing Peter was May's nephew, asked how Peter knew May. Not revealing his identity as May's nephew, Peter simply told Happy that he knew May Parker through Spider-Man, which Happy agreed. Before departing, Peter told Happy to take care of himself, which Happy reciprocated.
Morgan Stark[]

Happy and Morgan in Avengers: Endgame
Although they didn't have lots of time together in Avengers: Endgame, Happy was seen with Morgan at her father's funeral. It is believed that Happy met Morgan when she was born and had a close bond with her since then. At Tony's funeral, Happy asked Morgan how she was doing and asked her what she wanted. Morgan replied with that she wanted cheeseburgers and Happy told her that her dad loved cheeseburgers, whilst also telling her he would get her as many as she wanted if it cheered her up.