Copying the original text post here because it always seems to get deleted:

Throwaway to protect my and my girlfriend's identities. I met J almost four years ago at a campus club for young conservatives at our college. We clicked immediately and have been dating ever since. We have really similar values and perspectives on things -- we both lean toward the libertarian side of conservative, but don't like the childish attitudes of many libertarians; neither of us is very religious although we both do believe in a God; neither of us wants kids; and we like a lot of the same music and TV shows. Things have usually been great between us. We've obviously had our problems as a couple, but we are both good communicators and we have managed to work things out. I was planning to propose to her this September, on our fourth anniversary as a couple. However, as I'm sure you've guessed from the title, I am now having second thoughts. J's birthday is in a few weeks, and I love to get her presents she doesn't see coming, so I've been sneakily monitoring her online to see what she's interested in or looking at lately. Nothing like actually accessing her accounts, just looking at the ones I do know about and using them to find other things she may have posted online. (She is a big Internet person, using Tumblr, Pinterest, Instagram, Reddit and many others, and she often makes new accounts to preserve her identity.) While looking at her Tumblr -- which is normally Avengers gifs and funny text posts, with the occasional Republican content -- I noticed an odd post she had reblogged that seemed kind of implicitly anti-semitic, mentioning something about how Zionism feeds lobbyists in the US government. I clicked the username behind the post and what I saw shocked me. J had obviously reblogged a post she had made on her own side blog. It was unquestionably her account: the username was based on a nickname I sometimes use for her, the background was her favorite flower, the age and location fit, and there were a few other details I won't mention that cemented it in my mind as being definitely her. The theme of the blog was white supremacy. She posted and reblogged things like "black men are animals," "interracial relationships are disgusting," "Jews control the media," etc (except using not-so-nice language). Much of what she posts is even somewhat conspiracy theorist, blaming all the world's problems on Zionism. We have always made fun of conspiracy theorists together so this is really surprising to me. Worst of all, she posts pictures of "white beauty" and cruelly mocks pictures of non-white women, black women especially. And of course there was lots of recent political commentary about Baltimore, Ferguson etc, taking the right-wing position to the extreme and suggesting that black men should be locked up or shot on sight. This has honestly left me questioning everything I know about my relationship. My girlfriend is, in general, a lovely person. We live in an area that doesn't have a whole lot of racial diversity, but I have never seen her be anything but polite to minorities. She even has a close friend who is a dark-skinned Latina woman. And I really thought we were on the same page that it's someone's actions and behavior, not their physical appearance, that determines who they are. I have been accused of being racist before because of things like not supporting affirmative action, but to me this is beyond the pale -- it is past the line of legitimate political difference and into utter rabid insanity. I really have no idea how to approach this. My first instinct is to just break up with her without telling her why or talking to her about it, but then I remember I would not just be breaking up with the insane person I found on the Internet -- I would be breaking up with the woman who's been with me for four years through good times and bad, whom I thought I was going to start a life with. Since we don't want children, at least I don't have to worry about her passing on views like this to our kids. But I don't honestly know if I can, in good conscience, stay with someone like this. I guess I know I have to talk to her about it, but I have no idea how or what to say. I'm afraid she will just say "this has nothing to do with our relationship" and want me to move on. I am also worried because I have seen this strange, cruel side of her online that has never come out before, with her mocking strangers' pictures and calling them horrible names because they are black. I could really use some help piecing something together so I can deal with all this. TL;DR: I stumbled upon my girlfriend's secret racist Tumblr; she is a white supremacist anti-Zionist cyberbullying lunatic. What do?