I'm really happy for Colton. I hope he and Jordan make each other really happy. Watching his Netflix docuseries, it was super obvious he wanted to settle down and have kids. Not every gay guy has to sleep around, you know guys? If this makes them happy, let them be.
As regards how long should two people date before getting married, it truly depends. Sometimes people just click and work really well together. My parents dated for 2 months before getting married, and they were still happily married my dad passed away some years ago. On the other hand, my best friend dated a guy for six years, got married, and now they're divorcing after 2+ years.
These things don't really matter. Sometimes marriages work, sometimes they don't. There isn't a magic recipe you can follow to make things work.