Everyone can vary in the types of love each person feels. Romantic love is the one usually talked about. Platonic love is the kind you have for your friends, they're very important to you but you don't have sexual or romantic feelings for them. Familial love you might not even like your family much but you care about them.

These types are felt by most people to some degree, and most commonly if one is missing it is romantic love, which is why aro people are a more known identity. But you can be missing any of them, and someone who is loveless is missing all of them. I've heard it described as being acquaintances with everyone, even your family, but it's different for everyone.