Why is it that when you have a boyfriend,you dont rlly wanna hanhout with your friends..?

Like ik someone who has a boyfriend and I see how her friends ask her to hangout with her abd she dosnt rlly want to cuz she rather be with her bf 24/7 or on a friday night (n they live together).and I sorta feel lke dat too cuz I kinda have a bf too and when my friends ask me to hangout on friday..i kinda dont want too cuz I rarher be witg him....which is horrible n wrong..but idk why.?has this happend to u too?