You really sound like you're setting the stage for your husband to cheat on you with her. The things that bother you seem related to intimacy, hanging out with her drunk, inviting her over whenever she is sad, following only her social media, etc.

Consider that your mistrust of him may not be unfounded, you could be picking up on something. If you need outside opinions, you should consider interviewing some therapists and finding someone for you and your husband. Don't go to therapy because you want him to stop hanging out with her, but because this feels like a big issue to both of you and neither are hearing each other out. Get support before either of you does something that causes bigger harm to your marriage.