A place for atheists with cats to exchange pictures and anecdotes and even ask for advice regarding our feline friends.
Cara, the boyfriend analogy works in a negative way. It happens that people who let their cats outdoors find their cat starting to belong to another family in the area who put out food it likes better. Likewise, a boyfriend may leave you for a girl who pleases him in a way you don't/won't or with home he has more in common. Cats are not loyal. In fact, they may be less loyal than boyfriends.
A baby eventually grows up and leaves its parents, too. Friends may have other friends they like more than you. Boyfriends and spouses may have the potential to leave you, but I don't see how the possibility means they're not attached NOW. They choose to stay, which is more rewarding, IMO, than staying because of dependency or insecurity.
Dogs are more loyal than people, it's true... but if people (or babies) are the barometer for cat-attachment, then people are just as loyal and attached as cats... and dogs are the exception.
I do let my boyfriend out. I've had outdoor cats that never found another family. They could leave, but they didn't (and haven't). I think that says a lot about their attachment.
Cats are more adult than dogs, it's true. If they don't like the home you provide they can do the old "I'm outta here." It's more work to keep a cat. You can abuse children or dogs and count on their continued loyalty/attachment. Not a cat.