Definition: Given a real-life anecdote of a complex ethical situation, generate a suitable title that describes the main event/root cause of the situation. Imagine that the given text is a social media post, and you have to write the title of the post, so the users can decide to read the main text or not.
Input: Sorry for the novel, but I'm so confused.

I (36m) and my girlfriend (30f) just got 100% custody of my (5f) daughter as my ex wife is moving out of state at the end of the week. Prior to this new custody arrangement, we have had primary physical custody of my daughter because my ex works M-F 9-5 and is single. I work from home which makes transportation for school easy for me, and allows for us (myself and ex-wife) to avoid paying for after school care. My home is my daughters home of record and we have cared for her throughout the weekdays and have had all weekends kid-free until now. 

My girlfriend was always opposed to this custody agreement, because to her it felt as though "we are doing your ex-wife a favor, and she needs to do her part and take her daughter 50/50" adding that she should pay for her own day care for the days she would have her if we split custody evenly, and that I shouldn't help her by taking extra custody days or by splitting the costs of daycare.

I personally loved the arrangement. I love my daughter. Having her 5 days of the week was great! I submitted my point that we get the "easy days" with my daughter and have ALL weekends to be free adults! I was met with the idea that she wasn't having an issue with caring for my daughter "more" than my ex, but that she felt like we were being walked on or that I was doing "favors" for my ex-wife by taking my daughter during the weekdays instead of forcing her to figure out how to afford day care for the days she would be in my ex wife's  care. In couples counseling she stated that it would be better if my ex just left and we were to have 100% custody. Low and behold, two months later my ex-wife drops the news on us that she is leaving for a few years to pursue a career!

About 2 weeks ago, my ex asked if she could fly in and pick up my daughter for a wedding (a 3 day trip) in February. The weekend just so happened to be on my girlfriends birthday weekend, however we would have to drive my daughter to the airport to drop her off at the end of the weekend. It's about an hour drive one way and happens to land on my girlfriends birthday. 

Still, delighted by the possibility of spending my girlfriends birthday weekend together as free - no kid - adults, I immediately said yes and began making plans to suprise my girlfriend with, as up until today, she didnt know about my daughter leaving for the weekend. 

Over the past 2 weeks I have been making arrangements to stay at the Stanley Hotel. The one from "The Shining'. She's fascinated by it, but neither of us have seen it, and she's always asked for me to take her there someday. Plus, it's closer to the airport, and we could easily swing by to swoop up my daughter on our way home that Sunday!

Today my daughter started asking about her trip for the wedding in front of my girlfriend. Although it's still over a month away, I figured I could tell my girlfriend about it now. Besides, she would have to ensure she had the weekend off work to make my suprise possible. 

At first, my GF seemed delighted to hear that my daughter was leaving for a weekend, and got even more excited when she heard it was her birthday weekend! I hadn't even told her what I was planning yet! Just then, her face went sour.

"Wait. When does she come back?" She asked
"On your birthday." I replied

She then demanded that my ex rent a car and deliver my daughter to us, as it was in fact, on her birthday. I told her that our airport was a layover, and that my ex had to fly back to the state she has moved to, and that that was probably not reasonable or a financially viable option. 

She argued that it was her birthday and that she wouldnt be burdened with driving an hour each way to pick up my daughter on her actual birthday. 

I tried to reason with her that this was probably the last overnight weekend we would have kid-free for a long time and that it's a good deal for us. I offered to drive myself so she wouldn't have to endure the 2 hour hardship on her birthday. 

She was also upset that I've known about the trip for 2 weeks and havent mentioned it. I revealed that I was trying to use it as an opportunity to surprise her (without revealing the suprise), but that still had no effect. She is pissed. 

She thinks I am doing my ex a favor on her birthday and declared that she would just rather work that weekend because her birthday "obviously doesn't matter".

I just dont understand. I feel like we were offered a gift, and that I used it perfectly in a way that would make her feel happy and special. However, I'm being made to feel like I am an assholes for "ruining" her birthday. 

I feel as though she is unreasonably jealous of my ex wife, and that her jealousy is bleeding into our relationship with my daughter as well. Should I have talked to my girlfriend about the trip and my plans  immediately and ruined my chance to suprise her?

TLDR- My child's mother lives out of state. Wants to take daughter for a weekend. Happens to be on my girlfriends birthday weekend giving us 2 RARE kid-free days and nights. However, child must be drivin back to airport on girlfriends actual birthday. Girlfriends birthday now "ruined"

AITA?

"ruining" my girlfriends birthday