I'm copying this from a post I wrote in another thread:
1. The most important step I took was figuring out some financial goals, creating a plan for getting us there, and making a spreadsheet to show how it would work. I showed it to DH as part of a "date night" we set aside for the purpose. I explained about the safe withdrawal rate and the amount that I thought we could save by the time our DDs graduate from college (in about 8 years). With the spreadsheet, he could really see what we needed to do to get to where we want to be. I think a lightbulb went on for him at that moment, although it was still really the beginning of the process.
2. The main focus of the financial plan involved automatic deposits into investment accounts. I didn't focus so much on budgeting or cutting back in specific areas. Instead I showed how much we'd have to live on overall aside from what we'd be stashing away. Focusing on individual things, like cutting this or that area of spending, just caused DH to feel like I was trying to take things away. Also, automatic investing takes away the temptation DH has to spend $ on stuff just because $ is sitting around in the checking account. So rather than me having to be the scold, there's just a natural limit on our budget.
3. After I got DH on board with this new plan, then I started looking for ways to cut fat out of our budget. (Signing up for Mint helped with this.) I think this helped because rather than feeling like something was being taken away, it felt like we were adding $ to our budget by identifying where $ was going to waste and recapturing it.
I'm still in this process and taking it pretty slow. So, for example, about three months after I presented my plan and we started the automatic investing, I started talking about switching to Republic Wireless. DH was very skeptical at first—he loved Verizon and his iPhone —but the 30-day trial period won him over. I promised him that if he didn't like it we could switch back. While he still says he liked his iPhone better, he's happy with his new phone and realizes it would be ridiculous to go back to spending hundreds a month. He even recently decided all on his own to switch from the $40/month plan to the $25/plan, and he says he's perfectly happy with it. This is huge because getting the latest tech toy with all the bells and whistles used to be one of his things.
4. If you can, try to let some little things/small luxuries go. For example, my DH and DDs love them some Starbucks and it's something they kind of bond over. I know DH has been making an effort not to go so often so when they do I just bite my tongue.
So, for us, I think taking it slow and having defined goals are key. Before when I used to talk about cutting back, I think DH got nervous that I wanted to go to extremes, and he didn't see the point—he was one of those people who would say "we work hard so we should enjoy ourselves." Now I think he understands that we can make some pretty easy changes and still live luxurious lives, AND have a realistic goal of retiring while we're still young enough to enjoy it. So now he'll voluntarily suggest ways to save money, because he's gotten out of that mindset of feeling like he's depriving himself by doing so. Instead, it feels good to not spend excess money now, and I think that positive reinforcement will just lead us to want to keep going down the path of frugality.
All of this is not to say there haven't been any bumps in the road. Christmas was kinda tough, and in retrospect I wish I had just let some things go re: spendy presents he wanted to get some of his family members.
I should add that we were in a pretty good position to start with. We both make good incomes, have always maxed out our retirement accounts, and have never carried any debt other than our mortgage, which we recently paid off. So we didn't have that far to go.