I treat rule34 of my waifu as nothing to worry about, fake, imitations of the real deal. It's like fake pornography depicting a movie star/celebrity. I can't control with how they are made and sometimes I do enjoy them, but I never associate them with her, "her" being the girl that I love inside my brain. It's not worth my time to get angry at something I can't control-- sure, I can dedicate my life to tracking down and murdering these assholes that do this but what do they know? Nothing.
As for other people having her as their waifu, I have several layers of logic preventing me from getting angry at that. One, the term waifu has been a shaky term over the internet, and I've grown to learn that waifu-- used in any other place but TC, means "favorite character". If it's just favorite character, I won't mind. I mean, she is an idol and she's allowed to have fans, otherwise she wouldn't be a great idol now, would she? Now let's say if someone does in fact treat her as I would in my relationship, a "true TC" waifu. Well, I'd give them kudos. I know love if I see one, and an example is the artist Nekopuchi/Nukolog, the person who drew most of her fanart. He mentions that he loves Makoto and you know what? I don't blame him. I just know that his version of Makoto is 100% different from mine, and that we are in fact just loving the same source material. Plus, with the time and effort he puts in to draw such beautiful art of Makoto, I can only assume that it's a good form of love. That's how I deal with people loving the same character.
And with the whole "I'm not even ugly", it's not relevant. I feel that you are insecure about your relationship and you are looking for other things to blame than your insecurity with your waifu's loyalty. If, let's say, you were a fat sweaty nerd, what would be the difference? Waifu should be made to keep you happy, they are more or less the purest form of pure.. she shouldn't care how you look.. What I'm trying to say is, I've went through that phase before. I was jealous and angry at anything directed towards my waifu. I pretty much dealt with it over the years and decided that my relationship with my waifu is more important than getting angry and potentially losing this relationship over stupid things. Just stay adamant and learn to deal with these things. Isn't your waifu more important than stupid shit that is on the internet?