A theist asked, “What’s the deal with atheists not getting married, but building their lives together? To each their own, but doesn’t that make it easier for people to walk away?”
Here’s my answer:
Many atheists don’t feel their relationships with their significant others need the sanction of God and government. Thus, there’s not always a lot of reason for them to seek the sanction of God or government.
It’s not necessarily representative of a lack of commitment to one’s beloved; it tends to be more representative of a lack of commitment to the notion that people must obtain the permission of others for their lifestyle choices.