Assalamualaikum - My heart knows she’s right, but my nafs keeps pulling me away. How do I fix this?

Assalamualaikum, I need to be honest about something that bothers me. I’m engaged to a woman who gives me peace, stability, and helps me grow in deen. She’s modest, kind, and has helped me become a better person. We’re planning marriage, and deep down I know she has the traits that matter for a life together and for our faith. But my nafs keeps causing trouble. My past was full of chasing desires, attention, and appearance. Even though I’ve changed a lot, I still get triggered by what I see online or when I’m out. I catch myself comparing, thinking “what if,” and feeling restless about styles and looks, even though I know those things didn’t bring me real peace before. I’m afraid I might hurt someone good because I haven’t disciplined my nafs fully. I also know it would be wrong to ask her to change her modest dress or demeanour to satisfy my old habits. This is clearly my struggle, not hers. So I’m asking sincerely: 1) How do you retrain the nafs when it keeps dragging you back to old patterns? 2) How do you stop comparing and needing validation from outside? 3) For those who chose peace, stability, and halal companionship over past passions, how did you settle into that choice without regret? I’m not asking for opinions about whether to stay or leave. I want practical guidance on how to become a better man who decides with clarity and iman, not impulse. Jazakumullahu khairan. P.S. To be clear, she is beautiful and I am attracted to her. This isn’t about her being unattractive. She simply prefers very modest, traditional clothing compared with the modern looks I used to follow, and that contrast is what my nafs keeps reacting to.