Husbands female coworker touched him on his arm?

I was at my husbands work do and I saw that as she was speaking to him I saw her touching his arm.

She announced that she studies with my husband and looked at me directly whilst doing so, as if trying to see my reaction.

There is one class per week of around 30 others, most of which are female, who she could find to study with but instead wants to study with my husband who also attends this class.

Should I be concerned about this?

Husbands female coworker touched him on his arm?
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