In her article "Are Men Romantic?" on Psychology Today, Dr. Nancy Kalish, a professor of psychology at California State University-Sacramento, says: "Men may not make scrapbooks of mementos of their love experiences, but they are every bit as ... romantic as women---and sometimes more so!" This means that even if your boyfriend doesn't always treasure a birthday card, he will more than likely remember fondly the time you took to decide on what to put inside of it.
Instead of the standard "Love always," think of a special memory that the two of you have shared. This could be a funny story from a past birthday or why the greeting card reminded you so much of him. For example, if you chose one with a picture of a lake sunset because you watched the sunrise at a similar spot on vacation once, say something like "I want to love you all night long and watch the sunrise with you tomorrow, just like we did at the lake house last summer."
Put mysterious clues in your boyfriend's birthday card that relate to where you're taking him to celebrate. For example, instead of just putting the tickets in the envelopes, write down a few words of a favourite song from the artist or the numbers that relate to the stats of his favourite player if you are planning a fantastic night out to watch a beloved team or an idolised band play in concert.
Is you are planning a romantic night in for your boyfriend, complete with a candlelit dinner for two and other sensual activities, put a few directions for him to find out exactly what your've prepared on the inside of his birthday card. Simple things like, "Open the fridge and there you will find a bottle of wine... light the candles on the table ... I'll be down soon to give you your surprise." Sounds corny maybe, but it is guaranteed to get your man's mind racing at the thought of what's in store for him.
Photographs & Coupons
No matter what route you go with the greeting card itself, whether it be romantic, funny or racy, put a photograph in it. This could be a favourite snapshot of the two of you, or one that you had taken especially for the occasion. Make it a wallet size so he can stick it in with his other pictures or in a key-chain if he chooses to do so. A great additional birthday gift for your boyfriend, which can also be put in the card, is a few homemade love coupons. They may seem like an overdone present, but they are cheap and simple to make and no guy is going to care about clichés when he is holding the piece of paper promising something like a full body warm oil massage upon redemption.