I'm so sorry for the long prone

My (21M) friend Gavin (not real name) recently met someone and they've been flirting a lot. I don't like his boyfriend, but that's a long story for another time. When Gavin met the guy he's currently dating, I immediately found a shift in how we talk with each other and it's giving me so much anxiety that I am experiencing physical symptoms such as a heavy chest, stomach issues, nausea, and a palpitating heart.

Gavin and I met in July of last year. As soon as we met each other based on mutual interests and life experiences, we clicked immediately. We were talking every day and regardless of how busy we are, we reply fast and we always told each other about everything. This meant gossip in the community, our toxic parents, our sex lives everything. It's important to note that last year, we were still in online classes so it's possible that a shift to onsite (or face-to-face) classes can be an attribution to our lack of communication lately.

But when Gavin met the guy he's dating, it's like there was an immediate shift in how we communicate. Suddenly, he's not as communicative anymore, he doesn't share stories about himself anymore (when usually I'm the first one he tells stories to), and instead of a symbiotic relationship where we can both reach out first, I've been feeling like I'm the only one making the effort in the friendship. 

There are three significant events I can think of that's causing my anxiety to go haywire. First is, he is refusing to tell me any stories about him and the guy he's dating. I didn't think much of it, because when I date other people I don't tell him stories too. I have this superstitious belief that if I told anyone that I'm dating someone, it won't come true. I thought he just adopted this superstitious thinking of mine. But, he's been telling our mutual friend about his experiences with the guy. But again, they both dated the guy, so maybe the two of them are bonding through the guy, and he feels like I can't relate to him. He's not like this with the other guys he saw in the past, maybe he's also trying to prevent sharing stories that will make me hate the guy he is seeing even more (the guy is notorious for being a prolific cheater).

There was also that time when, the last event was when I invited him to drink with me. This one is 100% my fault. I invited him to drink on a Friday and he said he can't because of class, also I never clarified which Friday. Then, he told me he was going out to drink on September 16, which gave me a full-blown panic attack. That was the date I had in mind. When I told him this, he said I never clarified which date I wanted to drink. He thought I was inviting him to drink on September 23. I read our convos, and he was correct, I was the one who was wrong. He was nice enough to apologize though and said my feelings are valid, said that we both need to start communicating properly (he never put the blame on me) and that from now on he'll think more of me when it comes to friendly social events.

Lastly, is when I saw him tweet that the guy he's hooking up with (not the guy he's dating, also the guy he's dating is fully aware that he's still hooking up) used him to cheat on his partner. That sounded like something he would immediately tell me in the past. When I brought it up, he said he suppressed the memory and didn't want to talk about it. That's when it cemented to me that something really did change.

I know it seems so pathetic and petty, but fuck my paranoia and anxiety won't decrease whatsoever since he started dating this guy and there was a shift in our dynamics. I don't even mind if we don't talk every day, cause there were times we don't talk for a week, but he's showing a lack of interest in our conversations lately (or idk, maybe it's just my anxiety blowing this out of proportion). Since he started dating this guy though, I've had several reassurances that nothing was going to change. First, was when our mutual friend (the guy he's telling his stories to), said that Gavin is not comfortable declaring that they're boyfriends because all three of us (there are four of us in our friend circle) hate the guy he's seeing. Second, when he said that going forward after the drinking incident he'll think more about me when he goes to social events. Third, is when he told me that he is still excited to celebrate my birthday and New Year's with me.

Idk, my anxiety is fucking killing me with this. It's important to note that I am aromantic, so the concept of romance and relationships actually perplexes me. To me, it seems like friends are more paramount to the guy you're dating. I keep telling myself that there are other reasons why there is a lack of conversation between us and that things are just the same. First, of all, he has other friends from his classes that he is also socializing and communicates with. I mean, he's not my only friend, I am also in the same boat as him. Secondly, we're both senior college students, so he's probably busy writing his thesis and all of his requirements in class. Thirdly, he is dating someone, and despite being aromantic, I know that most of his time and effort will start going to that guy. Fourth, he's so tired from daily school stuff, his social battery can't maintain a conversation with me anymore. I mean, again that's a very fair assumption because there are times that I reply 5-10 hours after. Fifth, I'm probably overestimating how close we actually are.

Gahd I hate anxiety. I've been trying to keep myself busy all the time to avoid thinking of him, and nothing seems to be working. As soon as I am done with whatever activity that fills my time, I start thinking of how scared I am that he's drifting away.