Honestly, I don’t mean to be a dick, but I am kinda struggling with not being a total asshole right now. But since your question was a legitimate Ask and seems genuine, and you want to be more passionate to the woman you love, I will be respectful of that part and say what works for me, and I hope that helps you out.
First, your problem is in your outlook. Looks are such a small part of what I think about during sex. Clearly I am attracted to her or I wouldn’t be with her, but I have never been with a woman that didn’t have flaws, dozens of them, and if I look in the mirror, I see about a million, so getting hung up on skin tone or bruises or weight is a waste of time. You are setting yourself up to be disappointed forever and you will never really enjoy sex fully if you think about shit like that.
Second, kind of a side note: bruises can be hot, if you put em there, from a slap on the ass. Sounds fucked up but I am just being honest.
Third, in my mind, I am only thinking about one thing and one thing only. How can I blow her mind? Spreading her lips and devouring her and trying my hardest to pull one, two, three orgasms out of her before I switch gears and move to fingering her. Striking fear into her. A hand around the neck while she squirts and watching the beauty in her face as she wants to say “oh my fucking god” but can’t pull the words together. Slapping her to shock the fuck out of her as she was just settling into a relaxed zone. Fucking her and watching her eyes go from ‘that feels good’ to ‘don’t fucking stop you are hitting my spot’. To me – if you want to be more passionate – put yourself in that mindset – think about making her feel amazing, about how you can rock her world – and stop worrying about lame shit like her skin tone. You will never fuck a Beyonce because Beyonce, has flaws like everyone else. The version we know, doesn’t exist.
Last, she senses that shit. That’s a fucked up thing to put on someone else; the problem is yours, not hers. I hate to be a dick, but tough love is still love. I hope you take what I say and internalize and grow from it.