I am so confused. Is there something that has happened between them, that's I dont know of?

My boyfriend and I went on the trip with my best friend. During the trip, i got really sick, so i have to stay at the hotel most of the time. But i dont want to take the joy away for both of my boyfriends and my best friend. So i told them to go out and do thing together instead of being in the hotel with me. I saw they had a lot of fun together. After the trip we came back home at the airport he kept walking after my best friend and left me far behind , even after we got in line to get ours passport check he stand right after her while i stand behind them after few people in line front of me. As we have been in a relationship for almost 11 years , whenever we go somewhere, he always stands behind me because he says he just doesn't want someone else behind and accidently pumps into me. But somehow, now he stands behind her instead of me while i am still sick from the trip ( i went to ER during my trip with them ). After the trip, we go out and have dinner while crossing the street. My boyfriend walking next to my bestie have his hands on her waist while i walk right behind them ( basically, we cross street together, he walking with her and i by myself behind them ) . There are so many times he is very attentive with her, and i feel left out. She is single, and when they talk or look at each other, i can tell they have fun and are very close. After we came back home , sometimes when we talked, i mentioned to him that if i wasn't with him, if he and my best friend meet eachother they would end up being together. i said you and her will be perfect together. After i said that, he had no response. There's another time we talked about my best friend i said she likes you, and he has no response. Why is he acting that way? Is he admitted what i say as if we didn't be together and he meet her they will be end up together? And why did he stay quiet when i say she likes you? Does he already know that's she likes him too ( not as friends )

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The situation here is me and my boyfriend we live in the US. But my best friend she lives in Thailand. The reason we went on vacation together is because i took my boyfriend back to Thailand for the first time visit. I just want to spend time with my boyfriend and best friend together. After the trip, we go back to the US
I am so confused. Is there something that has happened between them, that's I dont know of?
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