I think she likes my friend more...

I have been dating a girl for six months and am beginning to think she has a crush on a friend of mine. She is always flirty when he’s around and I have caught her looking at him when she thinks I’m not around. I don’t know how to confront her because she may deny it and it may make things awkward between us, but it’s been on my mind. If she does like him, and decides to break up with me, it will be difficult for me to meet him because I won’t know how to deal with that situation. What should I do?
If there is something on your mind, the easiest way to deal with it is to talk about it even if you think it will be awkward. It’s insulting to assume your girlfriend is with you when she wants to be with someone else, because it implies that she can’t make up her own mind. If she wants to be with your friend, nothing stops her from having that conversation with him. There is also the implication that your friend has no say in this at all. Why speculate about what can happen in the future instead of focusing on the present where you are in a relationship with this person already?

How do I work through the anxiety I constantly feel while dating? I get so worked up that I end up feeling stressed and this shows. I rarely manage to go on second dates with anyone because they start to sense how worried I am. This is like a vicious cycle because it starts to ruin the possibility of me being with someone before I even go out with them. What should I do?
Why not start by telling yourself this isn’t a date at all? There is a lot of pressure you end up putting on yourself because you have expectations from how this is supposed to go. Think of it as a movie or dinner with a friend instead.