A lot of times we claim someone as our "best friend," and most of the time it's mutual. When that label comes out it's almost like you get the feeling that you can't hang out with other people, which is totally untrue. Of course, there are going to be people you're closer with than others but it is detrimental to a friendship when you label someone as a best friend and then expect them to only hang out with you.
I was listening to a podcast a while ago by Jordan Lee Dooley. This woman is a well of wisdom and she was dedicating that podcast episode to healthy friendships. She advised dropping the word best friend from your vocabulary because it makes other people around you feel like they're a second choice and no one wants to feel like a second choice.
A huge thing is not being jealous over your close friends hanging out with other people. It's really challenging to let that jealousy go when you see a picture posted or your friend mentions who they hung out with. I've felt that feeling hundreds of times. Let it go. Have an honest conversation if you must, but don't make them feel bad for having other friends because I guarantee you that you're still important to them and they still love you. That love doesn't just disappear when they spend time with someone else.
"Good friends call you whenever but a bad (or toxic) friend calls you only when they need something." How true is this that when someone you're friends with wants something. They'll call you or come see you and then after that, it's just kinda a text here and there. I've experienced that and I've also experienced being a bad friend. It's not fun when you come to the realization that you haven't been a good friend. But then you need to take steps to transform yourself into a better friend that truly cares about your friendships.
If you have a bad friend like that, then chances are you have the feeling that you don't know why you hang out with them. You're only as healthy as your friendships. It's okay to feel like you need space but doesn't do it all at once. That's a mistake I made once and it doesn't work to just drop someone, there's a lot of hard feelings and anger in that situation then. Instead, communicate those feelings you have and maybe spend a little less time with them but don't stop loving them.
The most important thing to remember is that everyone makes mistakes and no one is perfect. There is no perfect friendship and there might be jealousy, but that's where communication comes in. To be in a committed friendship, you have to have massive amounts of mercy, grace, and forgiveness.
Listen to Jordan Lee Dooley's "SHE" podcast and look up the "5 Ways to Know if Your Friendships are Healthy or Toxic," and check out some other episodes of hers, too.