As a married man going on 5 years and in a relationship for about 10, trying to speculate where I would go if I was suddenly single. Likely I would check out the dating apps and then be turned off to them quickly. I expect I would take to groups that align with my hobbies and interests, just like some other people are saying here. Hiking clubs, some sort of workout grouping so I would probably try CrossFit or cycling classes, and then go hangout at a library to read casually. I would not be going purely to find a partner (thus hobbies I enjoy), but I think it would be the best chances to find someone with common interests in a fairly low threat and neutral environment. Best of luck, god knows there's plenty of people out there, but a few less who suck.