UPDATE: I [25F] have to meet my mom's [57F] new girlfriend [59F] and I don't want to

I'm back. Here's the OG post, and the OG TL;DR in case the old post gets deleted because I think that happens sometimes?
OG TL:DR: My mom's a lesbian, I'm still figuring it out, and I have to go meet her girlfriend tomorrow. SOS.
To start, I went to my mom's, and was greeted at the door by my sister. She made fun of me because I brought 3 bottles of gas station wine because I didn't make a dish this year. Then, she went on about how excited she was for me to meet Kathy. I was about to ask where she was, then in true speak-of-the-devil fashion, she came busting in from the kitchen, squealing about how excited she was to meet me. Kathy gave me a kiss on each cheek, a huge hug, and asked me how I was, like she'd known me forever. She asked about how my presentation went (my mom told her I'd done a big presentation for work a few days ago), and then asked about my cats and if they were doing okay being boarded. She asked me to bring them next time, while she took me to the kitchen.
Seeing her and my mom together just made me sad. My mom gave her a big kiss when she walked in the kitchen, and it was the first time I'd ever seen her kiss someone we weren't related to. Kathy gave her a big hug around the waist, and my mom asked if she needed to warm up the mashed potatoes she brought. I knew Kathy was from Long Island, and had heard her accent previously, but I didn't realize how strong it was until she was telling my mom about how she brought the potatoes in a slow cooker. She's also a person who always yells, which is very different from my mom. I was feeling kind of overwhelmed, and just kind of bummed because I'd always had this acknowledgement of my parents' divorce, along with this really childish hope that I could Parent Trap them into being back together again?
I told my mom I had a migraine, so I took some Advil, and went to go sit outside for a little bit and cool off. When I got outside, I just started crying. My mom is really happy with Kathy, and I'm so blessed that she is. But I never thought I'd see the day where she'd be happy with someone who wasn't my dad. It was the first time I really realized and understood and knew that my parents were not going to get back together, and that my mom loved Kathy. I couldn't stop crying, and my mom came outside, and sat with me and hugged me. She asked if I didn't like Kathy, and I just shook my head because she's a nice person. I felt terrible for crying, and told my mom that I was sorry I was crying, and she just laughed. We sat on the porch and I cried, and my mom pet my hair.
She told me about how Kathy knows things about my mom that my dad never knew. About how her favorite color is the color of persimmons, because her own mom always had two in the house, how her favorite flower is a marigold, how she likes to wear her hair in two braids but never in one. And she told me all these wonderful things about Kathy- how she used to play street hockey with her son until she broke her arm doing it, how she rescued a kitten at the start of the year and takes him everywhere with her, how she surprises my mom at work every Friday by bringing her a pastry from her favorite bakery. My mom loves Kathy so much, and I just felt awful for ever doubting their relationship.
We went back inside, and I got to meet Kathy's cat. Dinner was awesome, and Kathy made some really awesome mashed potatoes. Both Kathy and my mom are less than religious, so they did a toast instead of grace- which we've never done before. My dad is very Christian, and we'd always say grace at the beginning of any meal. Even after they divorced, we still did it. Kathy said really nice things about my mom, my sister, and then said the thing she was most thankful for was the opportunity to meet me and for me to allow her into our family and into our home. I wanted to cry again, but it was an awkward moment.
The next day, we planned to go do Black Friday shopping, but Kathy and my mom slept through their alarms, and I didn't want to be the ass to wake them up. We just had a chill day, and got dinner at Arby's because my mom didn't want to do the dishes, and Kathy sucks at doing them. At dinner, Kathy kept telling us stories about my mom, and they just kept holding hands and giving each other little kisses on the cheek. It was the happiest my mom has ever been, even when she was married to my dad.
My mom told me that if everything goes well, she thinks she wants to be remarried to Kathy. I'm leaving for home tomorrow morning, but I feel better about it. My mom is with who she belongs with, and everything just feels right.
Thanks to everyone for the harsh dose of reality, and the care that it took for me to get off my ass and do this.
TLDR: Aside from me crying while everyone was cooking, dinner went really well, and my mom is very happy with her girlfriend.


Source.