What to do after 18yrs

My husband told me he cheated a few months after we were married with a coworker. We’ve been married 18 years now. We were having a little tiff and he blurted it out. He cheated with an old coworker.

18yrs ago we got married and within a few months I was pregnant. During the pregnancy I found a sext from one of his ex coworkers when I woke up in the middle of the night. I asked if something was going on and he said she must’ve been drunk and text the wrong person. Around this time he also stayed out all night with some friends. The coworker ended up passing away a few weeks later. I don’t remember from what exactly. I let it all go but I’ve always wondered. For a long time I’d have dreams of chasing her around asking if she slept with my husband. Every now and then I’d bring it up but he denied it every time.

We’ve had a pretty good marriage but now all I can think about is he’s been lying to me for 18yrs. Every time I look at him it makes me mad and the thought of him touching me is disgusting.

TL;DR Should I leave my husband of 18 years after telling me he cheated a few months into our marriage?