My best friend keeps on falling out with me what should i do?

[Liz]

So recently me and my one of my best of best friends keep falling out. I feel like for awhile now she doesnt like me as much as the rest of our friend group. So i still want to be friends with her so I try not to speak as much and try to be as nice as I can. A couple of days ago me, her, other two friends and my boyfriend went out. My boyfriend really likes to kiss me and hug me and i like doing it to tbh. But she said that she felt left out and i understand why and i know what to do for that situation but she has fallen out with me because of it (we have fallen out many times before).
I really feel like if our other friends accidently hurt her she gets over it and doesnt even care. But if I accidently hurt her than she will go in a huff with me and is angry with me.
I usually try to sort out our friendship when shes mad with me but if I explain how i feel or write her a huge paragraph (on facebook) how sorry I am. All she will say is "okay" or "cool". Please help me!!!!!