We've got a similar taste when it comes to deciding what looks good and what doesn't. However, we have a very different idea of what is the most comfortable everyday style of dress and how formal/casual we like to dress in day to day life.
He feels very comfortable in fashion sneakers, sporty looking trousers, a basic T-shirt, a hoodie and a shell jacket. He can and does dress very nicely, when the occasion calls for it. He actually has a very good taste for nice clothes, feels good in them and wears them well. It's just that his idea of when the occassion calls for less ultra casual clothing is different to mine.
I wear such clothes for sport activities and straight before/after them, or during a sport-oriented holidays (skiing trip for example), but I feel best in less casual clothing. My idea of casual doesn't look sporty. At all.
For example, my everyday casual includes jeans, but I feel better in trousers that aren't jeans. I like pullovers, but feel better in a jacket. A parka is practical, but a coat looks nicer and makes me feel better.
It's not unusual to see us together on a stroll or in a cafe, while he's wearing a shell jacket and sporty trousers, or a T-shirt and flip-flops, and I'm wearing a winter coat or a trenchcoat and leather boots, or a skirt and a nice top.
However, we often unintentionally colour coordinate. I don't know how that happens, but it's a frequent occurence.
Which means that when we dress in the same degree of casual, we look like a very well coordinated pair.
P.S.: I see I haven't answered your original question. Does my partner influence how I dress? Absolutely. He has good taste, so when he compliments my outfits, I trust his opinion. When I'm unsure about an item, I ask him for advice. When he recommends a piece of clothing in a style that's new to me or that I haven't noticed, I try it on. When he's critical of my style choices, I take a second look and consider them one more time. He's also very complimentary and encouraging towards polished and elegant clothing, which is in line with my own taste.