Hello, okay to start I am not trying to write a hate letter to anyone in a romantic relationship. As long as you are not snogging in my face I couldn't give an eff who you date. However, I have noticed how people change once they are in a relationship.
We are going to high school and many of our friends are dating now (some have been for a while). And I get it, you are a young teen and you are head over heels "in love" with this person and the concept of love is new to you, so naturally you want to spend all of your time with them. The couple then starts doing mushy movie couple stuff, and it goes downhill for friends from there. They are there making you feel like shit because you want to tell them to stop this, but you don't wanna hurt their feelings. The worst thing is that they have no idea they are doing that. The saying is "Love is Blind" but I think "Love is Blinding."
When we are teens we have so many hormones where everything runs at 100%. If we fall in love, we fall pretty hard at 100%. We let it consume us because it is a new feeling and what not. However, we can talk like this to a friend forever and they are like "OMG Yes, IKR, I hate it when that happens." Then comes the crushing feeling when they are doing those things you pointed out earlier. Let's face it though, most of these relationships are going to go downhill because this is not real love. You are hormonal, and as soon as you are attracted to someone (which is normal), you will start thinking deep into it. Your mind has been affected by media and you believe in love at first sight and all that. You will like this person for a while, and then you will grow older and find other people you like.
Before the relationship your friends are fine and cool with you. You two talk all the time, call each other names, and plan things together. You two wreak havoc when you go places and can sit together for long periods of time in silence. When they are in a relationship, their significant other(s.o) goes everywhere with them, if you talk to one, you talk to the other. This is uncomfortable for me. Here are some annoying things that tend to happen: They are always doing lovey dovey stuff, and its irritating to you because you remember that same friend telling you how they disliked that. And they refer to them and their s.o. as "we." Like NO you are not one person, you are two individuals. Oh Lord I have not begun to talk about the language involved, the "babe", "sweet", "dear", GOD DAMMIT YOU ARE 14 NOT 18+. And not only do they feel the need to express their love in real life, they also do it over social media. The worst part is the PDA(Public Displays of Affection). You know that painful feeling you get when you

see that friend, who was ranting about those two people on the train kissing, and they are one of the people kissing on the train. Your reaction is "WELL FUDGE, I THOUGHT I SAID THIS EVENT WAS SUPPOSED TO BE PG"
One time some friends and I went to the movies. And two of our friends are dating each other, so they obviously sit together and no one had a problem with it. At first it was fine, but then I guess they got bored because they started kissing. I was extremely awkward and uncomfortable for one of my friends because he/she was sitting right next to them and was sharing popcorn. Imagine reaching over to get popcorn because the person who was supposed to pass it to you was busy kissing.
I'm the end all I want to say is that I am happy you found you one you love :D, keep being happy. I have some friend who date other who are fine, I love them and I love their s.o. However, I hate that awful feeling I get when you treat me like the third wheel. That was probably Harry's reaction to Hermoine and Ron dating. Its not a good feeling at all, its sometimes painful to watch a friend drift away because they want to spend more time with their s.o. and you don't want to seem like a jerk by bringing up the awkwardness. When I date, I want a friend to hit me in the head with a log anytime I act like an asshole. You know I don't hate on love, I totally believe it is possible, but don't shut people out.