Eventually. Most people are in favor. Including some religious ones, actually. It's just not going to be that easy.


Edit:
To elaborate more: no, the EU cannot force countries members of the union to to any such thing, legally. The EU is not a federation, so that would only happen if the individual states agreed at some point to delegate to the EU Commission such a lawmaking power. Not only that is not on the radar - power delegated to the Commissions are not of this nature: they tend to be more economic or self-defense ones - but also, I am not really sure it would be a good idea to delegate such powers just yet.

I think it is more likely that simply Italy will adjust to a more and more popular sentiment, and will want to conform to a general EU trend. Also, what I think will soon happen, is that marriages celebrated in other countries will be recognized here to.

I actually like it this way much better, from a democratic stand point. The EU commission really is not in a position to play a role in such matters, and, as a European, I really don't feel much represented by that.
I'd love a true politically united EU, but it is just not there, so far, and what is there is quite "far", hidden behind layers of bureaucracy. If I only think of the 500 pages EU "constitution", that some wiser countries decided to reject, I am quite horrified. It was (is?) possibly bigger than the Soviet one. Oh my.
Again, I am all in favor of a united EU, and I'd love if THAT would bring more individual freedoms. But, we don't have that yet.