21 days is great! My DH continues to drink too. It makes it more difficult, but you CAN do this. If I did, anyone can! Hang in there and keep going. It really DOES get easier, the more time you have behind you.
BTW, my go-to drink in the past year has been:
1 squeezed fresh lime over ice with 1/4 c cranberry juice (I use low sugar), then fill the glass up to the top with lime seltzer water. It is SO refreshing! Give it a try!