My mother has been in a relationship with a man for over 10 years.
They met in the late 90s on ICQ (if you remember that early social networking application). She had just come out of a really bad and messy divorce from my father, and this man had come out of a divorce as well.
Mum and this man live together. They're common-law, in each other's wills, they share bank accounts. His kids and I are all grouped together as one family now. He makes her happy in a way that she never was with my father. And if she's happy, I'm happy.