How can I stop feeling jealous or anxious when my boyfriend goes out?

In my experience, I would reccommend communicating clearly with him about your anxiety and jealousy. It's usually a good thing to discuss any worries in a relationship, as it is a partnership. I would reccomend talking to him about the anxiety and jealousy you feel when he goes out, and ask him to work through it with you. It may be important to identify what might be making you feel this anxiety, and discuss that with him too.

Trust..... Trust is the only answer here..... Unless they have giving you reason to not trust them... You should trust them... Place yourself in their shoes....and see how you would feel if you wanted to go out with friends and your boyfriend didn't trust you.

The most honest answer I can give is to just try to trust him. If he is the type to not do anything that you don't want him to do then there is not that much to worry about. If that isn't enough to ease your nerves to jealously, then try to talk to him. A very important part of relationships is to talk to one another. If you talk to him about how you are feeling, and he cares about you, I am sure that you are able to figure out something that will work for both of you.