Mine has forgotten ours once. We had been married 6 or 7 years, second for us both, at the time. I knew he forgot because we would usually discuss where we wanted to go for a nice dinner, plus we would get little surprise token gifts of something we knew the other wanted. I had hoped that he would remember, but knew he had forgotten in my heart. I absolutely forbade our teen DD, mine bio, his step, from reminding him because she did remember.
When he came home, I didn't say a word, waited for a while to see if was pranking me because he had proposed on Valentine's Day in a way that was very disappointing at first as the ring was taped in a card that had a very busy design of swirls and circles so it wasn't obvious that I was getting more than a card. In fact, he had to actually tell me to look at the card closer. Anyway, it became obvious that he had totally forgotten our anniversary.
So, I put his token surprise gift and card on the dining room table and went upstairs to bed. Our DD followed me up and went to her room. After he had a beer or 2, or a mixed drink, I don't know which, he decided to come look for me because he wanted dinner probably. As he passed the table, I guess he noticed the card and package, apparently opened the card, and then I hear "Oh Fu....!" He came upstairs full of apologies, but I wasn't having it because there was no excuse for him forgetting. We got married within 2 weeks of buying our house, and we had talked about it being another year off the mortgage earlier in the week, anniversary was on the 1st of the month, plus it was a month that was important to us for another reason as well. So, there was no valid excuse to me.
I went on strike. Didn't cook for him or do laundry, and only spoke to him when absolutely necessary for a couple of weeks. Might sound petty, but it really hurt that he so totally forgot. I will say he didn't use his gift, a CD that he wanted but hadn't gotten around to buying yet, for months after.
He has never forgotten again, and I do have to give him credit that I got a heck of a Christmas present that year, then a really nice birthday present as well, the Christmas present a huge surprise as he came up with that one all on his own.
Believe me, I understand how hurt you are. Honestly, if it was me, at the very least, I'd text him and write Happy Anniversary to you too, then go for a drive or to a movie, call up a girlfriend and go to dinner, or something and don't sit at home. I probably wouldn't answer my phone for a while either, just text I'm out, will contact you later.
ETA: I got even madder the day after because he had the audacity to ask DD why she didn't remind him.
Oh, I guess I should add that we've been married for over 30 years now.