Is it normal for a husband to do this?

Any person who is already in relationship and even those who are single. If the keep giving space to a person, who is in love with them but still keeping them at arm distance but still close enough, are mentally sick people. They feed on some ones feeling for them instead of keeping a safe distance so that they heel and move on.

its sick beyong words to express. its like they playing with their emotions to feel good about themself. why not keep it simple, either let them in fully or just walk away but no, they will always have thousands explainations for this but to me, they are emotionally abusive to them and their love ones. I am sorry, if you are in this situation. He isn't a healthy person to be around.

I mean context matters. Is it a friend who's also a Coworker? Are they in a mutual group of friends? Is the girl who's crushing very lonely and unstable? Is she known to crush on a new man every once in a while?

It wouldn't be completely crazy as the wife to not mind them being friends. If she trusts her husband then she also trust that he'll set boundaries if the girl would try anything.

Is it normal to post same question again and again?

No, it isn't normal.

It sounds foolish, prolonged that third party relationship is toying with everyone's emotions and should be cut off.

I think this is very strange and would a huge strain on a Marriage.
Sally😣

I wouldn’t allow it