So..you've been married for literally 3 months and still in the honeymoon stage when both of you decided to go for a holiday. Travelling with tour where all your programs are taken care of versus backpacking is not the same. Backpacking requires a thorough planning and you're prone to making mistakes too.

You and your partner may get along very well but that doesn't mean you will during travelling. There are conflicts that can occur due to clash of opinions or perhaps plan. I've encountered them during my travel to India back in March. Staying together in one roof and travelling together are 2 different thing.

But, there are a few things you can do to avoid conflict with your partner/spouse:

Planning:

This is a crucial stage and backpacking is not a one man show. It requires everyone's involvement and in this case, your partner. Make sure both of you are in this together to make sure everyone is in the same page. Plan your itinerary TOGETHER.

Financial:

Discuss among both of you on how much can each contribute to your travel money. Be honest. The money should include accommodations, flights, transportation, buying souvenirs (if there's any), shopping and emergency funds too.

Attitude: 

I panic if my plan go wrong while Juan is the chill one even if the situation was bad. We had arguments during our travel and that is something you need to avoid because it shows vulnerability to strangers. When your plan fail, discuss in finding solutions. This has to be done together not one giving instructions to another individual. No point in pin pointing when things already happened.

Communication:

This is the most important element regardless during travelling or when you're at home. Make sure that your spouse/partner knows your plan and agree to it. If not, make amendment to your plan until both are satisfied or else there'll definitely be conflict. Remember that marriage requires 2 not 1.

Bringing another party:
If you think that 2 is not fun enough and you decided to bring along a 3rd party. Yes, you can but only if both sides are okay with it. Sometimes, your partner might not agree to your friend's idea and as someone who is not close to your friend, it's hard to express opinion.

Enjoy:
Enjoy your trip with your partner and don't stress up too much.