"Table tennis sounds like a like"...? Did you mean to say it sounds like a lie? Well, just because table tennis may sound like an 'uncommon' sport for you and OP, doesn't mean hardly anybody play it. Not only does OP have trust issues, but he is way too judgmental on his wife's interests. My apologies, but I don't understand how you understand his "worries".

They wasted two weeks of their life because they didn't believe that their partner had a hobby. That's pathetic that they have that little trust in their partner that they spy on them for two weeks.

personally I read it as that.. everyone seems to be jumping to conclusions, but I read it as "Fml, I'm an idiot for thinking she was cheating and I've wasted two weeks of my life". I read it as remorse to wasting that much time when he never needed to, and that he should have trusted her to begin with.