This feeling may be due to the secretion of dopamine. Dopamine is a neurotransmitter that transmits feelings such as happiness and excitement. When people experience something pleasant, the brain secretes dopamine, making people feel happy and happy. Being with him may make you feel happy and comfortable, which will stimulate your brain to secrete dopamine and make you feel happy.

In addition, this feeling may also be due to your comfortable and natural way of getting along and communicating. In a comfortable relationship mode, you can communicate and share naturally without much deliberate effort and pursuit. This natural way of interacting can also make people feel happy and satisfied.

Also, being with him may make you feel safe and stable. In a relationship, security and trust are very important factors that make people feel comfortable and relaxed. If you feel safe and stable with him, then you will probably feel very happy and content.

In short, this feeling may be the result of the simultaneous action of many factors, including the secretion of dopamine, a comfortable relationship mode, a sense of security and trust, etc. Whatever the reason, if you feel happy with him, then enjoy it!