Am I just being paranoid? Or is something really off?

My boyfriend and I are in a long distance relationship. We make it work and having been dating for over a year now. But sometimes I get really jealous of his relationship with his female cousin, which to be exact, is really the sister of his cousin's wife. So, no, they are not blood-related. Their bond is super close. They text, call, facetime, hangout, you name it, a lot. Sometime when I ask him why he doesn't spend time with me like that, he says that it's because I'm not there. But is that really why? Does he just not feel like trying for me? He has shown me their texts and I can tell that he cares so much for her. It's usually him initiating the conversation, asking her to hangout, talk, telling her he misses her, loves her, and stuff like that. Sometimes, I feel like I come second to her. I hate feeling that way. I don't want to be jealous of their relationship, but I just can't get rid of the feeling. I feel like he cares for her more than me. They see each other everyday but it's like they can't seem to get enough of each other. And whenever we have an argument, he always runs to her for comfort. I hate it. Please give me advice. I'm losing my mind. (maybe literally)
Ever since I became a child of infidelity, my trust issues have gone haywire. Life is crazy. Send me some help please.
Am I just being paranoid? Or is something really off?
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