I would say out of respect you would. How do you know that the mate or significant other would want to be the one that plans it? Or what if they were taking your friend out-of-town? Back in the days when your friend was single, planning surprises was easier but it doesn’t mean the element of surprise still can’t exist. You just have to be creative.
I know in our house my husband usually is really good at planning great birthdays. Now I do celebrate from May 1st until the actual day of May 10th. So that leads plenty of time for friends to do their own thing. He however is always the one on my day with the major of surprises. He welcomes others to do as they please but if its dinner, etc. he’s the one that makes that day special. If others contacted him he would be willing to make things happen.
It’s about respecting your friend’s relationship. You can still be spontaneous towards your friend. I have had friends who send me things to my house or work place and it catches me totally off guard. The ideal is to honor your friend and celebrate their Earth day. You can do that and still give space for the special man or woman in their life to be able to do the same. Who doesn’t like multiple celebrations? Dinners, luncheons, happy hours, brunches these are a few ideals that still can be done to honor your friend. You can do one day or in conjunction with the friend’s boo or separate and have a great time. Now if you don’t like your friend’s significant other, well there’s not much that can be done with that. However it cost you nothing to ask questions and clear the schedule. The significant other can even assist you in getting your friend to the location of your choice for a great guy’s catch up or girl’s night or day out.
Now I have heard some vindictive signficant others who say they have no plans and then when you do, they make them for the same day that you set aside. Keep in mind that your friend will in time see through this. Do not sweat the small stuff. Let your friend know way after their birthday what transpired.