Does anyone have advice on how i can break up with my boyfriend?

Hello, i need some advice on how to break up with my boyfriend. I am f18 and my boyfriend is m19. We have been dating for almost 3 years now and have known eachother since 14 and 15. We are in a long distance relationship, but we do see eachother like every 3 months. I am supposed to come see him on june 4th, and stay there until the 18th of june. Then he will take the flight home with me and stay at mine from the 18th-25th. I am DREADING this trip. I have been thinking about breaking up with him for about a year, due to how mean and how badly he treats me. He calls me names, shames me for my interests and is always starting arguments over small things. In march, my parrot passed, he had been with my family for 21 years, while my parrot was sick he got mad at me for not talking to him, while i was comforting my parrot. Then when my parrot was just about to pass, he was rushing me to talk to me and got mad i didnt reply right away. He seemed annoyed when i called him crying after because he passed. I tried breaking up with him about 6 months ago, but i got too scared because i do still love him and have known him for so long. I am scared for going to his house, because ill be there for 2 weeks. If an argument happens i wont be able to go anywhere, ill be stuck with him. Im also dreading having sex with him, because it has started to always hurt now and i dont enjoy it with him anymore because i dont feel loved enough. He also always ends up making me agree to sex in the end because i always begs or gets annoyed so i end up giving in. I also recently found out he has been watching porn behind my back, after we both agreed we think its cheating and wouldnt want eachother to do that. When i booked the flights i made sure to pay extra so i can get a refund if i decided to break up with him. I really want to break up with him before i go because i really dont want be stuck with him for 3 weeks. Im worried i will chicken out while breaking up with him, since i did once before. But i know that this relationship wont last with the way he treats me. So its better to get it over with. Does anyone have advice on how i could break up with him?