I might get jealous if my girlfriend spends more time with other people than me, but that applies to everyone. Since you're placing a lot of emphasis on cousins in this sentence, I believe it's important to take that into account. Hey, that's the point; they're just cousins, after all.

no, of course. I'm not a person who gets jealous easily, so yeah :/

why should i be jealous? if it's clear he is my partner's cousin i certainly don't matter, they are family and i'm just a foreigner so i have no right to be jealous. in the beginning i had faith in my partner and he was able to maintain my trust in him. that is enough hehe >__0

If my opinion, why jealous. They're both cousins, and there's nothing that can make me and him fight unless there really is something about my partner and his cousin (private direction) then I'm going to ask him why he's like that to me.

I'll talk to him first and speak out my worries gently. Better to talk bout everything, than keep it silence. Not an argue, just deeptalk.

No, of course. Afterall why would I get jealous of my partner cousin's?