The range of emotions for a new potential metamour

I've been having quite the week and wanted to come to the reddit to see if others have experienced this type of cycle.

One Sunday my partner went on a first date which she described as "wonderful" and called the chemistry with the new person "remarkable." We talked about it and she told me there's a strong chance they'd sleep together the next time they went out which has also happened this week.

As these days passed, I had a wild range of emotions. Heavy anixety and fear that my partner found a new partner and the descriptions of the first date and chemistry had me scared. Like, oh (#@!*) this is it, I'm OUT! I wasn't able to sleep well enough the last few days and even took a mental health day from work yesterday. Spent it in the gym moving some heavy weights around to get the energy out.

Today comes, and my partner and I talk and she's talking about how surprised she is at the connection, and when I expressed happiness for both her and the new woman, she says "See, it's reasons like this you are #*$&ing amazing." And with that, all of my anxiety lifted. We shared flowing words of love for each other and our relationship, and now I feel like I can get back to my daily grind of life.

But my question is this. For those who've experienced partners having excitement for new partners or potential partners, is this cycle of emotions "normal" or am I weird? I plan on talking to my therapist about it as well, but before I do that wanted to get the skinny here.

Hopefully you are all staying safe and having a great week.