I see a lot of videos and stories promoting cheating on your partner and doing taboo things and people finding out about bbc and go after that. The saying is “once you go black you’ll never go black”. Now I’m scared my future wife will cheat on me or think that someone else’s penis is bigger so she goes after that( finding out about bbc) or she’s seduced. All of these things are just constantly going over in my mind. Tips to overcome these thoughts ?

Well, that's a racial stereotype anyway, not a reality when it comes to penises. And I assure you, whoever you might marry in the future, they will already be WELL aware of this stereotype when they choose to date or marry you, and your penis, in the first place. EVERYBODY knows about this stereotype. And... I'm not sure how old you are, but it's not exactly a common thing to abandon your spouse out of a suddenly arising preference for a huge penis. There is more to a romantic relationship than your partner's penis. The vast majority of people are really not that shallow, just like most men wouldn't leave the woman they love because there exists a stereotype of blonde women with big boobs and they liked the sound of that, or because a blonde woman with big boobs hit on them. But sure, you might get abandoned some day after you're married because someone seduced her, or because she isn't feeling sexually fulfilled and as a couple you haven't managed to find a way around that (like sex toys or communicative sex lessons or opening the relationship). I'm sure that does happen occasionally- sexual chemistry is important. But you're thinking way too far ahead, and these aren't the kind of trust issues you want to end up bringing with you into a relationship, because they'll sabotage it, you could become overly jealous or controlling of who she spends time with or what media she consumes, or need frequent reassurance. I'd really suggest doing 2 things. One is response prevention: identifying your compulsions (analysing, ruminating, imagining scary future scenarios, looking for solutions, seeking reassurance etc), and not doing them, whenever you catch yourself doing them. Literally directing your attention to something else which is genuinely worth your time instead, even though that feels like a scary and negligent thing to do. The second thing is, instead of thinking about the details of your imagined future scenarios and how you could prevent it happening, to consider instead how you would handle it if it did happen. If you were happily married and one day your wife cheated on you because she had a fetish for black men with large penises and no integrity, how would you handle it? Who would support you? What other good things would still be in your life? How could you decide to rebuild? What choices would you have? Is another person's cheating a reflection on you or a reflection on them? Is a cheater/someone who does hurtful things needlessly, worth being with anyway? We can't prevent bad things from happening in life, whether we have OCD about them or not. They either will or won't happen, obsessing makes no difference except to make you suffer. Sure, you could live the rest of your life paranoid about this very rare thing happening, but it would definitely cause you to avoid relationships or sabotage them, I really can't imagine any scenario where being worried about this would make it less likely to happen. Having your heart broken is a risk that comes with being alive, unfortunately. You don't deserve to suffer with OCD, so do your response prevention. The thoughts can't be overcome by fighting them or trying to convince yourself that they're unrealistic, even if they ARE unrealistic and just feel scary. They can only be overcome by treating the topic like it's not important. Don't give it your thinking time.

maybe she will, maybe she won’t