How to fix this?

A girl I used to work with loves causing drama and making other people’s lives seem worse than hers. Mine wouldn’t be the first friend’s relationship she’s tried to ruin, nor first friendship she’s destroyed over a relationship. She’ll always include a little bit of truth in her gossip too. Honestly I didn’t know how bad she was til she did this. She’d been trying to manipulate me to break up with my fiancé for years. She’s made comments before about how hot he is but she’s made the same comments about me, so I’m not sure if she wanted me or a shot at him or if she just couldn’t stand seeing people happily together.

Anyway at a party she found out things had been rough for us after losing a pregnancy. We were fighting a bit, just bc we were coping with the loss differently, and that was partly why I went to the party bc my fiancé wanted me to get out and try to get my mind off things. She tried to get me to leave him but I looked at her like she was crazy and moved on to other people.

Later on I found her talking to another old coworker, a guy I used to be friends with but he’d had a pretty big crush on me. Once we both moved onto different jobs we didn’t really talk, and once I got engaged we stopped talking all together. He told me congrats, but it sucked that I was in love with my fiancé and didn’t feel the same way about him. So apparently she’d told him that my fiancé was abusing me and being controlling/manipulative and that I was thinking about leaving him since I wasn’t pregnant anymore. Cue the disaster.

I told him none of this was true and was extremely pissed. They kept exchanging knowing glances and saying I didn’t have to defend him. The guy is a paramedic and my fiancé just got hired to be a cop in the same city. The old coworker said that if he ran into my fiancé working as a cop he wouldn’t have any jurisdiction in his squad. Nothing I said changed what he thought, and it didn’t help that I was a little bit drunk.

I told my fiancé later it was a bad night and that I remember why I didn’t like my old coworkers as she always tried to start drama, but I didn’t tell him exactly what happened bc honestly I didn’t know what to say, he’s so excited about working for the police and I’m excited for him. I hate people who throw around abuse accusations when they don’t have the facts or know if it’s true, and the fact that she did it just to start drama pisses me off even more. This is his career, our life. I don’t know what to do now and I’m so worried that it’ll cause a problem down the road.

Update:

I’m normally a very open and honest person but yeah I have definitely learned my lesson on ever saying anything personal again. As for telling my fiancé, I’m worried that he’ll blame me. Things are finally good, and I had no idea that girl was such a bitch and would make up lies like that. When I told him it was a bad night he already asked why I went to the party when I knew that coworker would be there, and I told him bc he kept asking me to go out. I was finally happy and now I just have a lot of anxiety in my stomach that everything is going to be ruined