The gemara says that when someone brings a korban mincha in Yerushalayim he makes a שהחיינו. Rashi explains that he makes the bracha on performing the mitzva in an instance where he hasn't done this mitzva in a long time [see tosfos who argues].
Why don't we make a שהחיינו upon getting married?? Is it less a simcha than taking the arba minim or blowing the Shofar or bringing a korban mincha? I must admit that I was happier on my wedding day than I normally am on Rosh Hashana morning before the blowing of the Shofar.
In the sefer זכור לאברהם תשס"ה I saw an article where he collects 18 different reasons why there is no שהחיינו on getting married. My personal favorite: Every shidduch is filled with controver$y, so we can't make a שהחיינו given all of the distress people feel. It is a gemara ליכא כתובה דלא רמי ביה תיגרא - Every wedding involves some amount of machlokes. [From the Imrei Emes of Ger]
There is actually an opinion that one DOES make a שהחיינו before getting married.
Recently was the tenth of elul which was the birthday of the helige Tolna Rebbe ztz"l Rebbe Yochanan Twerski [after whom I named the yeshiva Nefesh Yochanan which is opening next Elul and surprisingly is STILL accepting donations and new students]. He often repeated the story of the Antoniner Rebbe who would ask why we don't make שהחיינו upon dying. The time of death is a magical moment for which we prepare our whole lives and we should be rejoicing in the fact that we finally meet HKB"H.
After lighting the Chanukah candle on the first night and making שהחיינו the Antoniner passed away.
Wonder of wonders.
More wonders.
The Rebbe ztz"l was very ill on the first night of Chanuka תשנ"ט and after he made the brachos - including שהחיינו - he refused to talk. His family members came to say goodbye and he made bodily motions but would not utter a word. It was STRANGE. That night he passed away and the family understood that he didn't want to speak after שהחיינו creating a הפסק between שהחיינו and his demise. So he too was זוכה to say שהחיינו before death like the Antoniner Rebbe in the story he was fond of repeating.
My eitza - Get married on the first night of Chanuka and then you too can make a שהחיינו for your marriage.
If it doesn't fit into your schedule then you can eat a new fruit or buy a new suit and have kavana that the שהחיינו should count for the wedding as well.