Should I text my ex a happy birthday after all this?! I keep going back and forth.

Okay so I’ll try not to make this too long but I feel I need to add details to get the best answers. So...my boyfriend of a year broke up with me almost a month ago. The reasoning for breaking up wasn’t anything major, he just couldn’t handle the relationship anymore (he suffers from depression, OCD, and anxiety so it was really hard for him to manage at times, leaving the both of us very unhappy) When we first broke up we were on good terms! We agreed it was for the best (even though I was really hurt) but we decided to stay friends....well then we got into a fight because he flat out ignored my kind message to him and I saw him talking to some girl on Facebook and it made me mad. So I lashed out and said some mean things to him (like 'I don't know why I even stayed with you for so long, you're just like my last ex' stuff like that) It was stupid and I made a mistake. I told him that, I admitted that I was wrong and I shouldn't have gotten so mad. He pretty much blew off my apology and gave me very short responses. So I stopped talking to him for a bit and then tried one last time, I wrote out a long apology and explained everything...I ended it by saying I'd like to try and be friends again if he'd give me a chance (we were best friends before the relationship, keep this in mind) He read my message (we have read receipts on) but he ignored it and never replied...I figured I'd never hear from him so I gave up. About a week and a half later he randomly text me "Hey..." so I reply a couple hours later with a "Hello." He again, read the message but never said anything. (it's been a week since he read it) His birthday is coming up in about 2 weeks...I want to wish him a happy birthday because I want to be the bigger person and I honestly just want to be nice to him because I feel horrible for the way I acted after the break up and I want him to know that I don't blame him and I'm not upset about it anymore...but at the same time I'm afraid he'll get mad at me or he'll ignore me again...I'm also afraid of breaking NC and regretting it. I just want things to at least be civil/on good terms between us. What should I do? ANY ADVICE WOULD BE GREAT, thanks so much if you read though this whole thing!!!