I've always had a pretty great relationship with my sister. I would say that, growing up, we've been best friends, a lot of our close friends are mutual friends, we've been on holiday together (just the two of us) etc.
She's been with her fiancé for about 2 years in total now. It's her first serious relationship; so, needless to say, it's been an exciting time for her. 'Dave' — as I'll call him — is a nice guy. I wouldn't have chosen him for her, but I do like him. He's honest, friendly and polite and they share quite a few interests. So my issue is not with Dave, but with how my sister acts around Dave.
This week they've been with our side of the family a lot more than usual, which is why the issue has become more apparent to me now.
My sister won't stop referring to her fiancé as 'my love' or occasionally 'baby.' This is near constant, to the point that she uses it without thinking — she accidentally referred to one of the family as 'my love' because she's clearly using it so much! Dave does say 'my love' too, but maybe once a day. My sister is using the phrase every other sentence instead of using Dave's name or 'you' when talking to him. It grates so bad.
Also, she's constantly making unnecessary comments about how Dave comes first. When one of the family propose an idea of an activity, she instantly says "well I'll only be participating if Dave wants to participate" or she'll clearly state out loud "Dave is the most important one to me." I'm 100% fine with a fiancé being the no. 1 in a person's life, but announcing it in front of your mum, your dad, your sibling etc., implies either that we were arguing the point (we weren't at all) or that we are unimportant (I know we aren't), so this also grates.
She is also constantly touching him, just really clingy. If we play a game, she's openly discussing how she can help him win, even though the point of the game is for everyone to compete.
Now, I'm not a very tactile person, and she is, so I appreciate that we are different that way. But judging by all the other couples among my family and friends, my sister is acting obsessed. I don't see my married friends all over each other, or even dating friends making 'announcements' to the group about how their significant other is more important to them than everyone else.
It may be worth adding that I am not in the wedding party but Dave's sibling is. Obviously, that was a joint decision, not just my sister's, but Dave doesn't know me all that well. Also, none of my side of the family is invited to hen nights/stag nights. I know some people choose to have friends only and not family for these nights, but I believe Dave's relatives are being included. I'm not super bothered about this (as long as I'm still invited to the wedding, which I am) but I think it might reveal where her obsessed mind is at.
To sum this up: Dave is nice and makes my sister happy, and I wouldn't dream of interfering in their relationship, which is clearly going to result in marriage regardless. I have no issues with Dave and Dave seems fine with my sister's words/actions/attentions. My family, including myself, have all made an effort with Dave to include him, to chat to him, to get on with him. The only change has been in my sister's behaviour.
I want to ask my sister to tone down the public displays of affection, particularly in front of myself. How do I go about asking her to do this? Judging by her recent behaviour, I feel that she may consider this an attack on her relationship with Dave if I speak to her directly about this.