How should I proceed?

Okay so I probably won’t get into the full meat and potatoes of the backstory with this current friend? But I’m not sure how to proceed with this relationship and have multiple other posts explaining what all happened.

So I (23 F) used to live with my partner (25 M) who for all intents and purposes will be called my fiance, and our friend/ roommate (25 F). She has two twin girls but they are a little irrelevant to the story. We can call my partner Ace and my roommate Dee.

Ace, Dee and I all agreed it would be best to move in together because she was struggling with rent on her own (her baby daddy is a deadbeat who was in jail at the time) and so was asking us to help out and cover where she was short on rent monthly for almost a year. My problem was I personally wasn’t paying my partner was due to their long standing friendship. After moving in together she practically refused to get a proper job, refused to clean up after herself and gave me attitude for even suggesting she doesn’t clean, and was talking mad smack behind my back after I had stopped talking to her during their fighting period (Ace and Dee… they were fighting over rent and bringing Ace’s family over from his home country)

After months of not being in contact with one another (specifically Dee and I) she asks Ace if she can come over to our place to drink, smoke and pretty much party with us while we had company over. I made it clear I was very much defensive of my space because since moving out I have been happier and maintaining our cleanliness a lot better. I didn’t want her to come over and start talking smack or disrespecting me in my own home. He allows her to come over and she isn’t too focused on me. She greets me and acts like we’re still really close friends. But doesn’t hold much of a conversation with me which is fair.

Eventually we had her go back home and heard nothing back basically. I thought this was the end and was honestly fine with it. But she invited us to her birthday celebration last weekend. Of course everything about it starts with Ace, so he’s the one trying to convince me to go. So out of respect for him I go, and told him if I say I’m ready to leave, we will find a way (we went on a boat for the day).

Dee was chilling, she and I were just chatting about stuff for the day but I wasn’t going to basically demand she talked to me about what was said or where she and I stand on her birthday. I enjoyed the party and we are both on good terms currently, but part of me is very much on edge with her. She called me a fake friend and some other really really mean/ hurtful stuff that goes against my character. So I’m not sure if it’s best to still try giving up being her friend at all or if I should try being a distant friend, not getting to close with her at all anymore. It makes me feel weird to say we are friends now but for the sake of Ace I don’t think I should completely block her off as a friend yet.

Ace was there for every part of the drama, he understands why I feel the way I do and I’m very intentional when I tell him if I say no/go/whatever then we stop whatever is going on and fix it with this girl in particular. The best way to describe it is in dog world (cause I work with them lol) if a dog isn’t too confident around others they tend to get picked on easily but help them gain their confidence and they start busting out corrections a lot more and know their own boundaries. I’m just building up my confidence :) thank you in advance for any advice/ tips.

TLDR; Dee, Ace and I used to live together before Ace and Dee got into our living agreement, Dee decided to say hurtful things behind my back and now that I know how she feels about me idk how I’m supposed to have her around currently because she isn’t full out of my life. She’s still close with Ace, and still nice/ cordial to me. How should I go about this relationship with her?