Heaven help you if you marry this woman, have kids with her, then wind up divorced.
She will do everything in her power to turn those children against you, she will go after you for everything you own. Those kids will grow up hating you.
If she’s being petty, jealous, and vindictive NOW with other people, she will be petty, jealous, and vindictive in the future with YOU.
Right now, you guys have been fairly “even” in terms of power, and she has been on her “best” behavior. She HAD to be on “best behavior” to manipulate a ring out of you.
Now, she has a ring on her finger and the attempts to gain power over you have clearly started. Her mask is slipping.
As soon as she gains even MORE power over you with a marriage, and then kids, for leverage, you will be treated exactly as she is treating your brother now.
She will seek to DOMINATE you fully – this will NOT be a relationship between equals.
She is CLEARLY high on the narcissism scale. Any and every aspect of your relationship is an opportunity for her to gain more control over you. She will undermine your own self-esteem, she will make you feel crazy with gaslighting, she will alternately hoover and discard you until, eventually, she grows bored of you and files for divorce.
And by then, your relationship with your family and any friends will be damaged beyond repair.
She has found someone who is quick to doubt themselves, and she is using that personality trait AGAINST you. She is manipulating you into thinking that “loyalty” means staying with a toxic, abusive partner. She is manipulating you into doubting your own mind and world view. She’s already insisting you discard your own world view and replace it with HERS.
HOW can you not see what she is doing????
She is evil. selfish, petty, vindictive, controlling, and manipulative.
Your brother was not being rude when he spoke the truth, which is that her behavior is a CLEAR red flag. Like, the clearest red flag you could ever ask for. He is concerned for you and for your future.