A lot of people say mate guarding is beta and I agree to a point, but there are situations where I want my LTR to be able to make a wise choice and I'll offer my advice and then all I can do is let her decide.

For example there is this guy who is a orbiter of my LTR. Let's call him C. C is beta as it gets, but he's overall an okay guy. He's into drugs and alcohol, which I'm highly against. I nearly broke up with my LTR due to her smoking when I clearly told her I don't want a girlfriend that smokes. She begged and cried so on for a week and I forgave her for that mess up, because hell it was the only bad thing she's ever done and would seem a bit petty to ruin a good relationship over something so small. The fact I don't like C is that he peer-pressured her into doing it and pretty much said "Struggles" will never know. Dick-move and imo ruined my respect for him. And this happened while I was working in Vegas for 3 weeks. I only found out because she told me and I have a pretty good gut I like to go along with.

So then I told her that I'm not comfortable with her being with C anymore and she told me she understands how I feel and really stopped hanging out with him for a good 3 months or so.

But I also understand that I don't have any say in who she can hang out with or not, but I like to make sure she's not surrounded by toxic people. I let her hang out with him and she use to ask me for my permission quite often, but I've said yes every time, because it's not really my choice. But she knows that if she does anything that I don't like that I'll move on.

My LTR respects me a lot, but to me this type of mate guarding is acceptable. Obviously mate guarding with plates is a big no no

TL;DR - Mate guarding? Definitely Beta, but also important for healthy relationships?