I [23F] recently ended an intense but toxic relationship [26F] and am now dating someone [23F] much more stable, but I'm worried because it doesn't feel the same.

As the title states, I recently ended a 4-month relationship with someone that was super passionate and SUPER unstable/toxic. When things were good, I was so head over heels in love. We spent all our time together, every love song reminded me of her, we would stay up at night just talking and cuddling for hours and I?d honestly never felt like that with someone. I?m talking butterflies every time we would see each other, from the beginning. However, she had a lot of issues (including what I?m now pretty sure is undiagnosed BPD) which meant she would swing from incredibly loving and affectionate to cold, withdrawn and mean at the drop of a hat. This made me so anxious which would make her pull away more, eventually, I would leave and she would chase me, the cycle would begin again. I recently had enough and broke up with her after receiving a particularly nasty series of abusive text messages and ended up having to block her on everything so she would stop contacting me.
I?ve been dating someone else for about 2 months (there?s some overlap, we were all seeing other people at the time & everyone knew and was on board) and things are going really well. She?s so sweet, affectionate, smart, we have really similar values and goals, the same sense of humor, good chemistry. I?ve been spending a lot of time with her recently and have been enjoying it a lot. She?s also really good for me; I made a list of ?green flags? after my breakup and she meets all of them (ex: kind to strangers, doesn?t play games, can be criticized without freaking out). However, I?m stuck on the fact that I don?t feel that immediate head-over-heels, butterflies every time we talk feeling that I did with my ex. I just feel very comfortable and calm with this person, which I know is good, but part of me misses that crazy love feeling and it?s making me overthink the relationship already.
I guess I?m just wondering if this is something worth being concerned about in my new relationship, or if my ex has me so turned around that I don?t know what healthy should feel like anymore. Advice?
Tl;dr After getting out of an unstable but incredibly emotional relationship, I?m dating someone who's really sweet and good for me...but I don't feel head over heels like I did with my ex


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