[UPDATE] I'm [28F] unsure if it's time to draw boundaries with my boyfriend [28M] and his coworker [late 20sF] who he got close to very quickly

Original post is here: https://www.reddit.com/r/relationshi...undaries_with/
TLDR of original: My boyfriend has become fast friends with a female coworker. She and her fiancé are now moving into our apartment building, and my boyfriend is seeing and talking to her more and more. I don't know if it's time to set boundaries or if I'm getting ahead of myself.
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A lot has happened since my last post, and I got some good advice there, so I wanted to post an update!
After I made the last post I came home from the trip with my family a couple of days later. I told my boyfriend that I wanted to talk to him about something and I brought up his friendship with Liz. I basically brought up all of my concerns from the post. I told him that I didn't want to discourage him from having a friend, but I also felt like they were talking quite a lot and spending a lot of time together, and that it was starting to make me feel uncomfortable.
My boyfriend took it really well! He immediately reassured me that he only saw her as a friend, and that he hadn't even realized how it could look to me. When I brought up how I felt like he wasn't being forthcoming with information (like how he didn't mention the phone call from her), he said that was 100% unintentional. He then immediately asked what he could do going forward to make me feel more comfortable. He offered to stop carpooling with her and to cut down on contact with her except for work-related stuff. I told him I didn't have a problem with the carpooling because financially it does make sense (he spends a lot of money on gas), but maybe he could try to text and call her outside of work a little bit less. I also told him I would really love to meet her and her fiance, and he enthusiastically agreed.
He set up a hang out for the following weekend - the two of us and Liz and her fiance all went out for drinks at a bar by our building (they'e moved in by now). It was actually really fun! It turns out we all have a ton in common. Liz and I do very similar work, and we all have common nerdy interests. It was a little awkward at first as meeting new people often is, but once we all got comfortable we had a blast. From there, we have all become fast friends, and Liz and I have developed our own separate friendship too. We text often, go over to each other's places for dinner sometimes, and hang out on weekends. I can honestly say I really like Liz (and her fiance) as a person and trust her 100%. I no longer have a problem with her friendship with my boyfriend at all. They do still carpool sometimes, but they've never hung out alone outside of work - it's always the four of us. I feel like a huge weight has been lifted off my shoulders.
Finally, I have a separate - but slightly related - update: my boyfriend is now my FIANCE! Less than a month after I made my last post, he took me out for a really beautiful and romantic dinner. When we came home, our apartment was covered in roses and candles. I was so shocked I could barely move as he got down on one knee and proposed. I said YES and then cried for about two hours as we called all of our friends and family. It was absolutely perfect and we are getting married next year!
It turns out that Liz actually helped him plan the proposal and that was part of why they were talking a lot too! Since she lives in our building now, he had all of the flowers, candles, champagne, and accessories shipped to her and kept at her place until he was ready for them. He even had her hold onto the ring the week before he did it. After he proposed she came upstairs and took photos for us and cried with us. That was the moment I realized what a great friend she is to both of us.
So communication saves the day again! We're all great friends now, and Liz and I have regular girls nights to plan our weddings together :)
TL;DR: I talked to my boyfriend and he introduced me to Liz and her fiance right away. We're all great friends now and I'm no longer uncomfortable - but I am engaged!


Source.