My friend and I split apart

Okay well I have this friend, me and her use to be really tight, but then the love of my life came around and me and her kinda split apart, I started hanging out with my boyfriend more and blah blah. My boyfriend and her where friends but then my friend made a small attempt to break us up. He got mad at her and they have been fighting since. My friend also complains a lot to me and it annoys the hell outta me. Also she can be really mean and annoying at times. I’ve tried avoiding her and not tlalking to her but she still thinks wee are really close. but I dont want to be her friend anymore but I hate being mean and I dont want to hurt her feelings by telling her I dont want to be friends with her anymore. My boyfriend said he would do it for me but I find that mean too. So what should I do… tell her or just avoid her or what…?