TIFU by giving my girlfriend’s friend too much attention.

For some context, my girlfriend and her friend (let’s call her Kayla) have known each other since playing soccer together in elementary school and have always been very close. For the past few years however, my girlfriend has lived in a different city than where we both grew up because of school and work. I recently moved out of town with her and moved into a completely different city. Though things have been relatively good, we have had our ups and downs. I am starting school and starting a new job, but for the first few weeks the only interaction I had with anyone was at the gym. Other than that all I’ve done is hangout at home and go around out on my own when my girlfriend is at work. It’s not hard for me to make friends but I’m not exactly the kind of person to just make it happen.
This past weekend we had planned on going to a baseball game in San Francisco and because they were playing Kayla’s favorite team we invited her to go. More context, also I’m about to sound like a scum bag, but Kayla is a very attractive woman. She’s big into the gym and just overall very charming and pleasant to the eye. I followed her on social media well before I had met my girlfriend and it was a coincidence that they were even friends in the first place. I never thought I would meet her though and considering the relationships/interactions with my girlfriend’s other friends I didn’t think anything would be different from the usual cordial interactions.
Kayla arrived on Friday evening and the game was on Sunday afternoon. I didn’t think we would hit it off right away until we started bantering to each other when she got there, mind you I’ve never spoken to her ever and the first time I’m making her laugh and felt full of charisma. It didn’t help that she almost tore off her front bumper on her car and I had to fix it. After she got there the back and forth was ongoing and it seemed like every conversation with her was personal and she looked at me for confirmation when we were all deciding on dinner. She seemed to be really comfortable right away and especially with me. We played cards against humanity and right away she didn’t hold back her humor which was funny because I most definitely held back my humor because of my girlfriend. We don’t necessarily always find the same things funny, which is totally fine, and sexual humor isn’t exactly our go to for laughs together. I also was surprised Kayla was so comfortable around me so quickly she made a lot of eye contact and honestly I couldn’t tell if that’s just how she is or how she was being with me specifically. Me and Kayla also have a lot more in common in terms of our likes and dislikes, we both love sports and we both love the gym.
Come the next day we all went and got food and had to help my girlfriend baby sit. Throughout that entire day Kayla and I had a lot of time together on our own and were talking basically the entire time. She laughed at jokes that were not funny and she seemed interested to know more about me. It almost felt like I was on a date, however I caught myself realizing that I was staring at her and catching eyes often and I could kind of tell my girlfriend was bothered by it or at least how much interaction me and Kayla had. We might have been too close on the couch as well, but truthfully I haven’t felt that much attention from a girl in a while because like I said things between me and my girlfriend have been okay.
It’s a lot of sitting in silence on our phones and in terms of physical intimacy there hasn’t been whole lot in some time and when there is, it’s hard to tell whether either of us are satisfied. That’s no excuse to make a move on her friend obviously, but just saying I hadn’t had that kind of attention in a while. Like I said I could tell that my girlfriend was starting to get bothered. She’s not very good at hiding emotions and when she’s in her head she gets quiet and keeps to herself until we have time to talk about things. I didn’t feel like I was excluding her at all during me and Kayla’s conversations or when all three of us were together. I was enjoying myself and just trying to enjoy my last weekend before being busy the next few months so I didn’t really take the time to dive deeper into the whole vibe. I guess Kayla and me laughing together and getting along so well made my girlfriend start to feel insecure. This was true for the entire duration of the baseball game and to the time we arrived back at home. I truly couldn’t tell what the vibe was after the fact or if she was feeling the same. At the end of the weekend though there was a lot to take in and I felt shitty because I could tell my girlfriend was feeling weird about everything.
Today Kayla is heading back home and I’m kind of sad I didn’t say “bye” to her before she left (I had work) but I sent her a message telling her to be safe and to not break her bumper again. My girlfriend and I are supposed to talk about how she was feeling today. I will update after we end up having that talk.
TL;DR
My girlfriend’s friend came into town and I ended up making my girlfriend feel insecure by how much we got along and spent time together.