Trying to put my finger on an emotion

Hello,

I have this nagging feeling I cannot shake and do not yet understand.

The cause of this was the following:
I still regularly see an ex, because my husband is his best friend (yes, awkward situation, to clarify, there are no feelings for the ex, it wasn't a serious thing from either side). He proposed to his current girlfriend, so I told her congratulations and she said: 'it's a good thing, right?' I was caught off guard by her (from my perspective) strange reaction so I was like 'yes! Or at least I think so?' ( I didn't really get why she asked a question like that) She replied and said 'Yes ofcourse, unlike you and your husband'
Her reply made me cringe (my husband and I love eachother, but got married for financial reasons when buying a house).
I talked about it with my husband and we would both like to celebrate our 10th year anniversary in a more genuine fashion. Even so, the nagging feeling is still there. I don't know what my emotions are (still) trying to tell me.

Anyone has some insights to share? How would you feel and why (assuming you would have gotten yourself in such in awkward situation in the first place)

It sounds to me she has been spoiled a bit on the nature of your union. It can come from the ex, and her own observations. It could have been a dig on you because her husband to be is your ex.

No one knows the true face of someone else's relationship. The outside appearance is often deceptive. For example, the people I know see me and my wife as one unit as opposed to individuals. They don't know the problems we have faced and are facing. The assumption is that because we have been together so long, we are perfectly happy. If we split up in the future, which is more probable than not, will be a " didn't see that coming" moment for those that know us.

My guess is the fiance in this scenario sent out some negative emotions to you for 1) being an ex, 2) judging what she has heard about your relationship from your ex. 3) solidifying her position as the SO with your ex. In other words, its her insecurity.

Seahound

I agree with @Seahound. I think she was marking her territory, a very, very common phenomenon in nature. I wouldn't give it another thought.