Is it normal to steal my boyfriend’s clothes and smell them?

Not taboo unless you're smelling sandtracks in his undies.

Not weird, at all. Actually, it's adorable, and quite normal.
Before I retired, from my construction company, I was on-the-road a lot. I'd ask my gal to spray some of her perfume, on a fresh pillowcase, and take it with me. When I got to the hotel, I'd put that pillowcase, on the hotel pillow, so I could fall asleep, and wake up, to the scent of my woman.
Once in a while, she'd throw a pair of her panties, in my suitcase.
Nuff said .... !

Its okay

It's normal. Sniff away.

I even smell my brothers hat when I miss him. He and I are best friends and he recently left for college and the smell makes me feel closer to him. Smell is one of our 5 senses and it can connect you with tons of different memories and emotions. It is totally normal, ESPECIALLY since it's your boyfriend.

How lovely

its normal hes your boyfriend and you love him

It sounds like you're one of those people who's more tuned-in to smells than the average person. There's nothing weird about that, and there's nothing strange about liking the smell of your boyfriend. Actually stealing his clothing isn't very cool, though. If he has any sense, he should be flattered that you want to have a reminder of him with you when you're apart, and he should willingly lend you used clothing.

We humans are mainly visual animals and most of us don't consciously pay a lot of attention to scents, but they do affect us subconsciously. There was a famous experiment a few years back that found women preferred the smell of men whose genes were most likely to combine with their own to produce a child who was healthy. Summary here: https://www.pbs.org/wgbh/evolution/library/01/6/l_016_08.html

There's a much longer article about the role of scent in human attraction here: https://www.psychologytoday.com/intl/articles/199603/the-smell-love

I suspect you don't hear your friends talking about the smell of their boyfriends for the same reason you feel a little embarrassed to talk about this: in our society, we've been brainwashed by advertising to believe that natural human scents are nasty, and we should scrub them away often and conceal any odours that appear between bathing with perfumes.

Absolutely normal.

😵😵😵

Pheremones.

Ask him first I doubt he'll car3.

Normal.