There is really no 'one way' to express love. Similarly, there is no set formula to make your partner feel special. Sometimes small acts of love (helping around the house, taking care of the kids and supporting the partner's career) can brighten your partner's face. But if you want to do it with a big gesture, how about doing an activity that you both enjoy together. If your partner loves adventure, try hiking together, if you both enjoy watching a movie, go on a movie date, if you both like traveling, book tickets to a place you both have never been too.
There is no symbol as such and if it there be then it is perhaps the bonding that you have with him. You know what would light up his eyes. And it can be a humble meal at home or a holiday at an exotic place. I guess, love is such a special thing in itself that even the most boring things don't appear boring when done in love. Do whatever comes up in your mind and trust, your husband is going to like it hands down.
I don't think there is any particular "symbol" for romance. For some, a day without arguing and getting on each other's nerves can be considered romantic hahah. If you do want to show romance, do whatever that is sincere to you and your partner. Cheesy as it sounds, it's the thought that counts.
"There are as many ways of loving as there are people in the world." Same is true for love symbols. There are as many symbolic expressions so there is nothing like a new symbol of romance. Classics like candlelight dinner, long drive, small surprises, gifts always works.
There is no particular symbol as such. Do whatever your partner and you feel romantic about. Personally, going for long drive, long walk along the beach, weekend getaways or just sitting at a cafe having long chats is very romantic.