A cuckold. These guys spend half their lives imagining that they are being wrongfully denied sex by women with the temerity to have relationships with people who aren't them.
"Snowflake" is another disparaging one that was quoted in my timeline today i.e. people who think they are unique and special. "You lost snowfalke, deal with it" etc.
There's also a whole load of racist shorthand they come up with to avoid being banned from twitter etc.
wtf is a 'cuck'