I tried to fix my bad thoughts but I think I made things worse

Just a heads up, maybe sensitive content? So I struggle with being hooked on inappropriate stuff and daydreaming a lot. I decided to quit those haram things and work on my mindset, because they bring thoughts that shouldn't be there. I'd rather not go into details. Anyway, I was trying to 'correct' my thinking by replacing it with something halal that's kind of similar. I told myself that intimacy after marriage is okay. That might sound normal, but in my head, it was just like: someone proposes, they have a wedding party, and that's it. I don't know, at the time that's all I thought about, and it didn't feel like a proper Islamic marriage, you know? I can't really explain it, haha. But now I'm worried that I convinced myself something haram is actually halal-like believing intimacy is fine just after a proposal and a simple wedding. I realized this many days later, and I can't even remember when I started thinking like this. Now I feel like I'm back in that cycle of committing kufr, having to make up prayers again, and all that. I just can't put it into words anymore.