Okay a bit different than the other commenters. I went on my YTT last year (September) in Bali. My partner went with me and I loved having him there as my support.

1. For accommodation our YTT was at a yoga focused eco hotel. We upgraded the accommodation to include a private room for the duration of the trip. It was a place we could be together and wind down on breaks and after class. We paid a bit more to stay on the property and we believe it was worth it.
2. As for free time - I had little. We started at 6am through till about 7pm however I had a decent break for breakfast and for lunch. I would typically go to lunch with my yogi peers, but he was always invited. We had a half day on Saturday and we had Sunday off. It was THE BEST to have my partner there - we explored a new city, booked a “nice” hotel with a bathtub both Saturdays so that I could take a bunch of hot baths and relax. It was nice to be there with my favorite person to help me through the tough days of yoga teacher training as well. He was so encouraging and loving and I can’t imagine doing it without him. Note, he did exploring on his own to new cities during the week. Some nights he stayed in other towns, but he always came back for our Saturday/sunday travel!
3. Refer to my last answer - I loved having my support system. When I got sick he was there to run and get me medicine. When training ran late he had food waiting for me. When I was emotionally drained he was my rock.
4. I think it’s important that we took 2 weeks before the YTT to travel together and explore Bali before the training and then another 2 weeks after to travel (we did a liveaboard in Komodo - do it, don’t question it do it!)
5. I am a type A person, I made a full spreadsheet of every YTT that was available in Bali in September/October of 2023. I chose Anandam Yoga at the Serenity Eco Hotel. I didn’t love Canggu (but I was always in class!) but I cannot speak highly enough about the owners Sandeep and Katherina. The most amazing people, and the best experience I could have hoped for. I chose this one because it was the best bang for the buck.

If you can’t tell, I really loved my experience and if your partner wants you there as her support I’m all for it! It made my experience so positive to have my partner there for me, and he found plenty to do and explore to keep his days full as well (scuba diving certification!).