Do what ever you can to prevent picking up any bugs (in the first place)
which may aggravate the sinuses.   ...I keep a bottle of Purell (alcohol
hand wash) in my vehicle, that I use religiously whenever I get in my
vehicle... Even if it's just after stepping out to fill my gas tank.
..As a result, I haven't had a cold or flu for over 10 years now, even
though my business puts my in direct contact with the general public, on
a regular basis.  (Moreover... Conciously, keep your hands away from
your nose and eyes)

..And no. 2 ....   Do what ever you can to avoid blowing your nose.  

..Everyone of my flair-ups has followed my ignoring my own advice and
forcefully trying to clear my sinuses.

 ...And 3...  Keep up the irrigation.  ...The one time I had what felt
like a flu, turned out to be a blocked sinus.  I couldn't flush nothing
out either.  Then it all came loose in one lump chunk, and I felt
instanty better.    ...Thus... If I feel a flair-up coming on, I'll step
my irrigations up to 3 or 4 times a day.

and #4... Drink lots of liquid.    Good luck..  Jon

The fact that both of you get sick at this time of the year suggest that
it's viral; and that when one of you catches a virus, the other one then
catches it from that person.

Here in the Northern Hemisphere, these viruses spike in September
because that's when kids go back to school and start sharing their
viruses.  So the most effective way to avoid these viruses is to stay
away from children, and NEVER touch your nose or eyes without thoroughly
washing your hands first.

If one of you gets it, the other one needs to practice a similar
strategy of avoidance.  BOTH of you should wear masks and gloves when
you're around each other.  (When I was a kid and my mom caught a cold,
she ALWAYS wore mask and gloves to avoid infecting me.)  And needless to
say, don't sleep in the same room at night.

There is some evidence that inhaling warm steam, both through your nose
and mouth, is helpful.  Not just because it dilutes phlegm, but some
have theorized that warming up the inside of your mucous membranes helps
prevent the viruses from multiplying (they thrive best at 94 degrees
Fahrenheit, the usual temperature inside your nose).

And nasal irrigation is terrific for stimulating mucociliary clearance
which promotes healing.