Struggling with a Broken Friendship and Abandonment Issues

I'm struggling and doing my best to push through and not let it get to me..... my sister inlaw and I useto be really close she was my FP she was mine and her brother's biggest cheerleader when getting married about a year ago or so she accused me without talking to me messing around with her husband I WOULD NEVER I'm happily married and she cut our friendship off cold turkey I haven't been the same since I mean other than my husband I held such high value for her she was my FP I can't talk to her I can't even look at her without wanting to fall apart. My hubby is my FP and even I feel he's pulling away I feel like his one parent is main priority over me and I know its just my other demons as I like to call them whispering and don't get me wrong when he hangs out with this parent yes at first it hurts but then I realize I kinda like the alone time but I swear my abandonment issues go full swing initially.