To close for comfort

Okay you guys I need some advice, or maybe I'm being over paranoid. But I've been with my boyfriend for a year. I feel like him and his sister are way too close. I think there could be more going on but maybe I'm just bring over dramatic. Well my boyfriend and his sister always text each other and have to beat each other by midnight of who says i love you the most. He's taking her to Disney world in august by himself without me or his family. She's 18 and he's 32. They are always talking. She doesn't know anything about me or that we are expecting a child. He left to go to Texas to be with his family this weekend. He brought his sister a engraved 200 Dollar bracelet and a jewelry box. It's had hearts with diamonds in it and then said her name and infinity and beyond I love you the most. Well then he sends me this text last night that made me weirded out. And then today he hasent texted me at all besides his sister just left. I said so why can't you talk this was at 10 pm at night and I haven't heard from him since. But here's a message from him from last night. She had to call him every day and tell him what's going on and off they don't talk she gets mad and upset and he always goes into another room to talk to her. But then when he gets in Texas and she picks up him he says he's getting in the car with her and that he can't talk anymore. She gets mad when he's in the phone. Then he texts me at 930 saying he's been busy her and him are watching a movie at home together hell talk to me later. I feel like I'm gojng crazy I have never had a relationship thos close with my brother. Then I ask him why inst he wearing his ring on his left dinner he sais cause she doesn't know anything about us and the baby so I can't wear it. So I took my engagement ring off and not wearing it now. He comes up Sunday. I'm sure that it's his sister they have pictures together and all and she lives with their parents. The Disney trip was just planed the end of may. And we been together for over a year. I don't know how to go about this talking to him. Like I feel like I'm super jelous of her and I shouldn't even feel that way. Plus on wendesday night he sends me a picture of her dress and said he wants to match with what she's wearing and asked me to go his closet and get a nice tie and shirt that matches the same color to her dress which was a dark blue. And I just tried caling him to talk again and he completely shut his phone off.