I love my GF very much (she is 29, I'm 26). Backstory: Earlier this year , her cousin who she hasn't seen for over a decade, flew down to visit. In the beginning of our relationship, he flew down and we picked him up from the airport, had dinner, visited Mt. Rainer, etc. They were speaking Vietnamese the entire time, but I've been trying to learn the language since then, and he knows English good so we could talk! Yesterday, my gf asked to hang out with the family (2 brothers, mom, and dad) because her cousin is only over for 3 days. I said yeah that's fine But this time, it seemed like he teased me and her a lot, and made some jokes that just didn't really sit well with me. While at the Viet restaurant, he mentioned jokingly to my gf oh look he's texting another girl (when I went on my phone). My gf kinda looked up and didn't really smile but looked confused / worried, then they started laughing. It felt kinda awkward Then a few moments went by and we...