Do other women find you intimidating?

I've begun to question this, as I can't fathom any other reasons as to why women act the way they do towards me, from supposed friends to even my husband's family members.

To preface, I'm a pretty nice person and dislike gossiping. The only people I "gossip" with are my husband and absolute best friend. Talking about others just to talk about them has never been my forte. I'm shy, but at the same time I am extremely confident and put on a good act - everyone is shocked when I tell them I'm shy and have social anxiety.

I've been told by many that I am gorgeous and I do get a lot of male attention- unwelcome or not. I am extremely fit and am an NPC bikini competitor. Yet, I don't brag about any of this and actually don't talk about myself at all. When I talk to others, I like to ask about them instead of focusing on myself.

My husband is extremely fit and handsome as well and we have been told that we make a power couple. We both have great careers and are educated, but don't flaunt it. When the two of us are together, we are the most popular couple in the room. Yet, when many women talk to me alone, they seem non-genuine and fake. I always try to be as humble as I possibly can - please bear in mind that I am saying all of this to provide backstory.

My SIL (husbands, brothers girlfriend, same age as me) is one of those women. She talks badly about me to my husbands extended family and I've noticed times where I'll walk over to join a group conversation and she'll shoot me a glance, grab another girl, then announce loudly that she "needs" to go to the bathroom, where they undoubtedly go to gossip. She's very quiet and when it is just the two of us, she'll act friendly but in a group setting I always feel like she's irritated by me or my presence. Ironically, we used to be friends and I set her and my BIL up. Now she just makes me anxious... I feel like she's a complete snake.

If it were just her that acted this way, I wouldn't be bothered but since I've gone to college and started to take care of myself, women have started to act this way toward me, and therefore I have never had many female friends.

Ladies, I know that was not nearly enough of an explanation, but can anyone empathize? Has anyone else been through similar situations?

Is it that some of us are intimidating? Are we doing something wrong?

And, do any of you have issues with a potentially jealous SIL? I may make a separate post regarding that...