It could very well be a beta instinct of wanting to provide and care for. I'm not sure mate guarding is the best description, as I'm not a very jealous person.
I get that, maybe the key to spinning plates is to make less effort(Less providing), thus displaying higher value, making it easier to spin plates.
But I don't know if I have it in me yet, as the beta provider is very strong. I.e it makes me feel good.
I don't really think that's a "beta" instinct, but I think those terms, alpha/beta are so overused that they lack meaning anymore. (Ditto "Chad".) If a sultan provided ample food, clothing and shelter to his harem, is he beta? Lol.
What you're describing is normal. Same as women like feeling protected by a man. You just have to be careful not to take it too far. If she hears a noise in the basement, you're going down to check it out. She sees a spider, you kill it. After sex she puts her head on your chest. Those things are organic. It veers into "beta" when you start going out of your way to do every little thing for her, or coddling her.
I've always felt the best balance was a little danger/adventure + safety. Women love thrills but they like coming down from them into a man's arms. Heck the whole 50 Shades franchise is based on that. If you're worried about it resulting in you catching feelings (and you don't want that), you can always pull back a little on the safety part. Our behaviors often dictate our thoughts, not just the other way around.