A Benny 473 might be a bit big for just the two of you. Just remember, if you're cruising as a couple, much of the time you're actually sailing single-handed, since the other person will be sleeping, cooking, reading, etc.
My general recommendation is that you get the smallest boat that will work for you, rather than the largest boat you can afford. The running costs go up with boat size, as do the maintenance costs.
You could probably find a very nice 37-40' boat that would suffice for the two of you. Traveling with a dog is doable, but you will find that the restrictions on dogs will limit your choices in where you can go. For more information on the pet issues, you should check out www.noonsite.com
, which has a lot of information on the various countries that you are interested in visiting, including, IIRC, pet restrictions.
Another recommendation I usually make is that you should reserve 15-20% of your boat buying budget for refitting, upgrading, modifying and repairing any boat you buy. No boat is going to be setup exactly the way you want and you'll generally want to modify it or upgrade it in some way prior to leaving—so leave yourself some funds to handle this.
The last recommendation I generally make is that any boat you buy should be setup for the way you will be using for the majority of the time you're using it. This comes from the advice a friend gave me that said, "The primary use of a boat is primary
." In other words, if you're mainly sailing as a couple, chances are likely that you don't need a three-cabin, two-head boat. By going with a two-cabin, single head boat, you will reduce your maintenance costs and the complexity of the systems on-board... although, with an extended cruise a two-head boat might be nice, since it gives you a backup head.