I think my (31F) husband (33M) has a crush on his new coworker

My husband and I have been together for 9 years now. I know for a fact that he would never do anything but just the idea of it makes me feel uneasy.
He recently got a new job and he very quickly became close with his coworker Diana. The way he described her to me made me think she was our parents age, stating that she was a recent divorcee with 4 kids and a grandbaby on the way. I met her 3 weeks ago at his work function and found out that she is only 38 years old. She is also one of the most beautiful people I have ever met, she has all of the physical qualities that I lack.
This makes me feel very insecure because of how much my husband talks about her. The first thing he says every night after hello is a new Diana story. I pretty much know her entire life story because of how much he talks about her. He has also alluded to the fact that she tells him things that she doesn?t tell anyone else.
I always see him texting her and giggling at his phone which made me so upset that I read through his messages while he was in the shower. (This was a moment of weakness and I completely understand how disgusting this behaviour is). Although I found nothing sinister whatsoever, I was still taken back by how many inside jokes they have and how much they chat.
At his recent work function, he was following her around like a puppy. He usually holds my hand when we are walking from A to B but he didn?t even try at this function because he was walking next to her. When she wasn?t around he would go searching for her and when she was around he would pretend like I wasn?t there.
I have no animosity towards her because she was very pleasant with me during the night and had mentioned me frequently in their text messages. I just feel very insecure right now and want to know if this is a normal experience.
TLDR: My husband has gotten close with his new beautiful coworker and I am feeling very insecure.


Source.