Looking for realistic advice for a situation

I want to preface by saying my OCD has been exponentially better. I haven’t even posted on here in months which I used to do obsessively. With that being said, I have an ex from four years ago. He truly struggled with mental health and did some crazy things. It was an incredibly toxic relationship. He was reaching out for a while and then stopped. I blocked him every way I could but he has recently been reaching out on new accounts he’s created (on Instagram). According to a message he sent, he knows about my wedding which doesn’t surprise me as I have a public website and he likely looked up people I know that posted wedding event photos. I block his news accounts but it’s happened twice now where he creates new accounts. I even choose “block this account and future accounts by this person” option but it doesn’t always work. According to Google he could be using a different email or IP address to create these accounts. Anyway, I’m far removed from this relationship. So much as I’m getting married to the man I have been with for three years. I guess my OCD comes in when 1. I convince myself I did something like reached out to my ex to spark his attention (even though I know I didn’t do that) and 2. That’ll he find a way to contact me on my wedding day since he likely knows the date. Any time he reaches out it sets the mood for a day fueled with anxiety and trying to figure out why this is happening when the simple answer behind it is he truly has problems and is crazy. Does anyone have advice on how I could NOT ruin my wedding/the days leading up to it in fear that my ex is going to reach out and ruin it? Obviously it’s presumptuous that this this will happen and my reaction likely won’t be anxious like it typically is as I’ll be quite busy caring about the day, but nonetheless I am fueled with anxiety thinking about this possibility.