If you were in a long term relationship and discovered your partner had an active dating site profile what would you do?

Think tinder, bumble, hinge, badoo, okcupid, pof, eharmony and many more similar ones.

I'll even go so far as to include Onlyfans, Allmyfans, etc. in this as they are basically still 'dating sites' or more like 'baiting sites'.

How would you confront your partner about it? Would it be an instant relationship ender and if married a trigger for divorce?