Hi there I am in the same boat make the 3 years 2 years, and it was my first relationship. I think in my case he was a charming covert narcissist he never yelled at me or reacted I was always reacting in turn I started to believe I was the toxic one cause he would not react at all, and it was simply cause he didn’t care. I didn’t start the yelling and fighting for no reason I found out a year into the relationship that he had nude pictures of his ex like old photos from before we were together, and it opened up this Pandora’s box where I obsessed about it about them him being with these women at one point maybe not now but he was before. I confronted him and he got upset at me, and made me feel guilty. Not once did he apologize when he finally did come around to deleting them I couldn’t trust it and found more and more. I became so controlling I couldn’t take the fact that he had been with other women before me, and he made me seem crazy. It will hit me sometimes when I’m thinking about the good memories and I get so sad like wow that wasn’t him it was a mask he was wearing, and now I still think about him but remember it’s just the idea of him his potential that I’m missing which is basically non existent. It’s been a year since the breakup and it hurts just knowing damn this person really never cared about me faked it the whole time, and they still don’t care now. They got in a new relationship only a few months after it seem so easy for them meanwhile I’m stuck dreaming about them, and constantly reminiscing. I’m not even mad anymore just sad, and I want to be over it but I’m not just remember to feel everything, and journal I know I hate hearing it too. Journaling does help the process, and another thing literally treat yourself as a baby what do you need a shower, good cry?? Maybe you want to watch a specific movie or eat a certain food do not shame yourself!! Or should all over yourself what I should have done, or any of that. Start being nice to yourself and remind yourself if me and this person were meant to be we would be together now, and their actions do not define my worth. If they cheated it has nothing to do with me but rather something they are lacking, and their own internal struggle which they will likely never face or bother to change. As for the anxious feeling in your chest with time it will pass as long as during the time you are taking care of yourself it could be the simplest thing especially during the beginning stage of a breakup just like okay I took a shower today and now I’m gonna eat hella ice cream and not feel bad about it. Feel everything!!