who’s side do i pick?

so i just recently i have been taking to this guy (nick) and things are getting pretty serious. Everything is great with him for the most part but i’m having trouble making time for him and my best friend. My best friend let’s just call her “Riley”. So riley is the one who set me and him up ive known nick for around 10 years we grew up together and have went to school together but riley is the one who made us start hanging out again and pretty much set the relationship up. But she’s became jealous because i stopped spending every day with her. most the time i am with him and i can see why that would upset her but i have been making time for her too i spend at least 3-4 days a week with her and i feel that is enough but she gets so mad whenever i hangout with nick instead of her. sometimes we even all 3 hangout together but me and nick like to spend time alone too and she doesn’t like that. nick gets annoyed with her and i can understand why because she’s always stuck up my butt. so who’s side do i pick? or how should i handle this? i love both of them very much and i don’t want either of them to feel excluded from me but i feel like they’re fighting over me.