I'm not sure if boring is the word - she frequently mentioned that he had hobbies, fishing (which he still does with the girls), football, martial arts etc. and that he enjoyed listening to music/attending gigs for example. However these were things Sophie didn't enjoy and so they weren't shown.
I think he spent a lot of time building his business and he was also an active bodybuilder in both weight lifting competitions and the shows.
They still travelled etc as she does with the dentist but, unlike the dentist, travel wasn't the be all and end all.
He didn't drink which is what I think Loaf found annoying. She adopted this persona to fit him when it really wasn't here.
I also don't buy the "the twins couldn't come to America because it makes Nath anxious" story. She knew they were off to Disney, LA and then Coachella. There was no way two six year old children were ruining the fun. Either she has said it won't be suitable for the twins or he has not wanted to let his children spend that much time with someone their mum barely knew, which is a valid concern.