Traveling together can very well prove to beneficial for carrying out a healthy and strong relationship. Here is how you could actually make it possible:
Know them better: Spending quality time together is the best way you would get to know your partner more better. Spending time within the city has got it's own limits and that's why taking a long vacation or going out together will improve the chances of knowing each other better.
Tastes and likes: It's not always the behaviour, but also the likes and dislikes. While traveling and enjoying a vacation together we tend to know about the overall personality of your partner. You could even reveal a lot about the adventurous side of yours too. By doing so you get a better connect among yourself.
Sharing the space: Traveling together means not only spending time together, but also sharing the same space together. This will tell you if you have the comfort zone together and if sharing the same space with the other person is possible or not. This reveals habits of the other person that normally you wouldn't get to know.
Making your own space too: Sharing a common space does not imply sharing a room or house alone but it does mean carving out your own space even after staying together. It is a sure fact that you both will have varied interests and you may give each other that space, then it's all going through right direction.