If you've been lucky (or hard-working) enough to find a partner in life who shares your interest in personal development, congratulations! It's so much better to know that your partner supports you in your struggle to become the best you, instead of having to deal with someone who's trying to make you skip your princinples and join them, the potato chips, and the Kardashians on the couch when you're trying to do something productive.
What's more, you don't only have to support your partner in their journey - you can have mutual rituals and principles that support the both of you even more, while making you feel more connected as a couple.
One of these couple hacks that will help you stay principled or make a lifestyle change is an agreement.
The agreement is a written and signed piece of paper that entails a description of the desired principles or lifestyle changes of both parties, and a description of the penalty, in case one or both parties fail to honor the agreement.
This could mean basically anything, but let me give you an example to demonstrate the agreement. Say, you want to quit smoking, and your partner wants to start waking up earlier. You type (or write by hand) an appropriate heading and then state, "partner 1 will not smoke another cigarette or use other tobacco products", and then "partner 2 will wake up at no later than 5 am" (add timezone) "from Monday to Saturday". Then describe the penalties: "if partner 1 fails to honor this agreement, they will pay partner 2 100 dollars per day, every day they fail to honor the agreement", and then "if partner 2 fails to honor this agreement, they will pay partner 1 100 dollars per day, every day they fail to honor the agreement". You can add more clauses, like when the payment is to be paid. You can change the penalty and the specific resolutions as you please. The penalty doesn't have to be money - it can be disliked household chores or anything else unpleasant.
Remember to add place and date and signatures at the bottom. You don't have to show the agreement to anyone besides yourselves - you don't have to get a notary to validate it (I think the agreement is completely enforceable as it is). It's enough that two people, both of whom want to make the change, are committed to it and honor it by paying the penalty when it's due.
Keep the paper somewhere where you can see it every day to remind yourself of it.
One more thing - if you think the agreement, with payment to the other party, gives that other party a motive to try and make you break, you would be right. But if your partner truly is on your side on this, they will support you, in the hardest part (the beginning) at least. After a while, if they try to lead you into temptation, you will have acquired a relative immunity, giving you a chance to grow stronger by resisting it.