How do I get over my married coworker?

We listen and we don’t judge. Ok I (28F) know this is wrong but I got myself involved emotionally with a married man (39M) Who is also my coworker. We didn’t do anything physical but we mostly communicate over text/DM (involving sexting and sending nudes). In person now though we keep it pretty professional and just act like friends. I suspect he’s a narcissist. I attract em. I feel like he just replaced my narcissistic ex and shifted my focus. But he’s obviously a player and flirts with everyone especially another coworker of mine who is twice my age. And she’s jealous of me for more reasons than one. And I feel like she’s trying to gain his attention and trying too hard. It’s bothering me a lot which is frustrating and making it hard to exist at work. I feel like he’s low key triangulating us but doing it very slyly. How do I set boundaries and get over this and just focus on my job? It’s a VERYYY small office so I cannot avoid them and I hear all their conversations at work(a lot of them are sexual). And yes I am working on finding a new job.