I suppose if you are wanting a public marriage to support your secret marriage, it should be all right, but you should check on the laws in your place of residence (talk to an attorney) to make sure you will not run afoul of some rule.
I would say yes. Actually, my grandparents secretly married (so the story goes) and then had a public wedding later. It doesn't hurt anyone. I think if people, though, are spending money on a wedding like your or his parents, they would be upset to find you were already married. Pay for it yourselves (you and your husband)-- and then no worry of that being a factor. Does anyone know you are married already besides the two of you? But I don't see why you can't get married publically now to live like man and wife under the approval of family. So, I say go for it!