Usually not because of the date. A date is not news. He already knows what day it is. The day coming back does not mean anything else came back with it.
If you would not text him on an ordinary Tuesday, today is not a better reason. It is just a harder day. His birthday is a little different, and we will get to that.
Free to try. We never store your chats.
Some people will tell you a short "thinking of you" is harmless. Others will tell you never, under any rule. Both are talking about exes in general.
What you have is more specific. Maybe last year he sent "happy anniversary" first. Maybe this year you have typed it twice and deleted it twice. And the voice says: He has to remember. He is probably with someone. 1 text can't hurt. Those thoughts are about the date. None of them is about what has happened between you since it ended.
Put the date aside and look only at the thread after the breakup.
Missing him on your anniversary is not a message. It is just today being hard.
A birthday is about him. An anniversary is about the 2 of you. "Happy birthday" is something friends, coworkers, and old classmates send. "Happy anniversary" points straight at what ended. They are not the same weight.
What you want back. If you want a reply, ask yourself what reply. "thanks" will feel worse than silence. If only "i miss you too" would be okay, the text is carrying a question you did not write.
Who ended it. If you ended it, a note on the date can reopen something he has been trying to close. If he ended it, he may read it as you asking to go back.
If you are on okay terms and you would send a birthday text to an old friend, you can send one to him. Keep it the size of a birthday text and ask nothing. Something like: happy birthday. hope it's a good one.
No question, no "remember last year," no opening for a long talk. He can answer with 1 word, or not at all, and neither will hurt much.
For the anniversary itself, the honest answer is that there is rarely a text that fits. If there is something real you want to say to him, it will still be true next week, on a day that is not doing the talking for you.
Sending nothing today is the better move on most anniversaries. It is not giving up. If you want to reach out to him later, see is it too late to text my ex.
You paste the thread. It reads today against him rather than against the calendar — how it ended, what has happened since, and whether anything has changed lately or only the date has.
Then it writes the message in 4 tones if there is one worth sending, and tells you if the better move today is to wait instead of sending anything.
Try it on your conversation