I really wish they could have given him a story not about an affair. It trashes his character and makes little sense, and we don't even get to see him naked.

When we met Tommy, he was pretty much settled down; he was the most sane of the bunch (if not the most boring).  He had no particular life to explore, so I doubt there were many avenues for the writers to take his charachter.  I'd expect him to feel immense guilt when his wife comes home (probably about two or three episodes from the end of the season), confess everything, fire Lena, and everything will be alright.

I must agree though.  I wouldn't mind seeing him shirtless a time or two...