I KNOW I was very inactive these days but I really wanna say smth

Have you guys ever felt left out?
Bcz I feel that often these days =(
My 2 friends are best friends, they've been friends since they were 6 or smth ig
I met them later on
I like them a LOT and all,
But t h e n I realized that they like eachother m o r e

I KNOW that I MUSTN'T feel sad about it
Bcz they're best friends and they totally must keep their friendship together and all,
But still, I can't help feeling sad about it
So I tend to get moody whenever I hang around with them
And I'm worried that It would be a trouble to them or smth
Don't get me wrong, they are very nice, and they were very nice to have welcomed me to there friend group, and I totally understand about them being bffs and I am MOST CERTAINLY N O T COMPLAINING OR ANYTHING
but I can't help feeling sad =(