Pretty close, and perfectly understandable, but some tweaks:
...The first years of their marriage were *very* happy...
...She asked him what the reason for this was,
Bob continued coming home drunk almost every day, and Beth became more and more apprehensive.
The couple's peace was lost, and their arguments were constant.
Depending on what style you want in your writing you might change that last bit further to something like "The harmony that the couple used to know seemed to have been lost forever, and...."
I rather like that last clause "..., and their arguments were constant." It's a little unusual in "normal" English but here it has a slightly poetic feel to it. :)
Hope that helps