My boyfriend, who identifies as straight, is flirting with the guys in my family.

To begin with, my boyfriend (21M) and I (21F) have been together for about five years. I believe in expressing love through all five love languages, so I do expect the same in return. I care for him deeply, but I've noticed that throughout our relationship, I've often had to either ask him or teach him how to love me—just the basics, really. Over time, he has learned to show me affection. However, recently, I've observed that he flirts and banters with the guys in my family. Initially, I thought it was all in good fun, but I've started to realize that the way he interacts with them is completely different from how he interacts with me. In fact, he hardly flirts with me at all anymore, which is disheartening since I'm always trying to flirt with him. It’s disappointing to see that he can be playful and flirty, just not with me. I've brought this up to him at least three times, and while he has been understanding and promised to flirt with me more, it seems that for every bit of extra flirting he does with me, he increases his banter with my male relatives. It feels frustrating that I still need to request affection from him—it’s honestly a bit sad. There was one particular instance when my boyfriend went to a rave with my family, and I noticed him flirting with my guy cousin. The smile my boyfriend gave him seemed so genuine, whereas when he looks at me, I often just get a half-hearted smile. This makes me constantly seek reassurance and affection from him. I trust him, and I genuinely believe he wouldn’t cheat on me intentionally. But am I overreacting, or are my feelings valid?