You can give or not give your ex-boyfriend a wedding gift, but if you already have your current boyfriend, you can still give him a gift if he agrees. And if you say you are still friends, then you must give him a gift. It doesn't matter what the gift is, the most important thing is the blessing.
For a wedding gift with beautiful blessings, his wife should not say anything. My suggestion to you is to give them a real wedding doll, the kind that will grow old together. The effect is very realistic. They are very creative and funny when placed at home. I believe they will be very happy.
Or give them some gifts in pairs, such as personalized tags, on which you can write your sincere blessings to them. Hehe, his wife should not be jealous. Besides, you are very open-minded when you give it, so don't care about these.
That's all. I wish you good luck and I wish you can enter the palace of marriage soon!