Sudden insecurity/jealousy?

My husband and I have been together for 4 years, married for a year and a half.

I’ve prided myself on never getting jealous!

He’s a friendly guy and his friendliness could be seen by others as flirty.

But I’ve never let it get to me because I trust him 100%!

He started going to the gym recently and taking a spin class. He loves biking in the summer and wanted something to do in the winter.

Recently he added the spin instructor on Facebook. I have to admit, she’s gorgeous!

She posted on her wall asking for people to give her song suggestions for her to play at spin class...

My husband commented about 15 songs all links to YouTube...

One of the songs was our song. A song we both shared and listened to when we first started dating.

Out of no where I have this insecure/jealous feeling.

I still trust my husband and know he would never do anything even close to cheating...

I feel like it would be a huge overreaction asking him to stop talking to her on Facebook or stop going to spin class.

Is the whole situation an overreaction on my part?