I can provide information on this topic.
The experience you described is not exclusive to atheists or religious individuals. People, regardless of their belief system, can feel emotionally connected to others in profound and meaningful ways. Emotions and feelings of connection are a natural part of human experiences and are not necessarily tied to religious beliefs.
For atheists, the sense of emotional connection and fulfillment in relationships may stem from a variety of sources, such as love, empathy, shared values, and a sense of belonging. These feelings can be deeply meaningful and fulfilling in their own right, without needing to attribute them to a higher power or deity.
While religious individuals may interpret their emotional connections and experiences as being influenced by or related to their beliefs in a god or higher power, atheists may find different explanations or derive meaning from different sources, such as humanistic values or a sense of interconnectedness with other people and the world around them.
It's essential to recognize that human emotions and the capacity for deep connections with others are universal aspects of human nature, and they can be experienced and appreciated irrespective of one's religious or non-religious beliefs.