I had the same issue with my husband. About 10 years ago, fresh out of college and just married, I hated my job. I did the numbers and figured out if I lived in a tent on public land and ate nothing but ramen noodles we could retire in about 3 years. My husband's response, "but I don't like ramen noodles". Apparently camping was not an issue for him!
Fast forward ten years, two babies and one large mortgage later and I was back to contemplating that tent (another low point in my career, to be honest). Before you even start on your journey, you've got to set a goal. I had to be specific with what I wanted to accomplish by spending less and why (how it will impact our life). So, for me, I want to work fewer hours so I can focus on my health and my family. My husband knew I was unhappy at work, and unhappy with my health and with my general lack of energy that kept me from interacting with our kids. He wanted to improve that, too. So he knew what I wanted to achieve and we also talked about what HE wanted to achieve until we had one common family goal. This is key, it has to be a joint goal. In my case, even if the goal mostly impacts me (work fewer hours), it ultimately is about a better life for all of us. I reiterated this goal several times in multiple conversations to lay the groundwork for my master plan. The more you say the goal out load, the more it becomes a reality. After that I implemented the following:
Step 1. Track Your Spending - This is a vital step, I use Quicken but you can do in Mint for free. You can't cut expenses if you don't know where its going.
Step 2. Cancel the Stuff No One Needs or Uses - I mean the stuff you don't remember you're buying that he won't even notice. For us, this was a couple of magazine subscriptions, an out-dated subscription to the consumer reports website, and some other little things.
Step 3. Cancel the Stuff YOU Don't Need (And That He Won't Notice) - This is stuff of your own that he doesn't care about. For me, it was a few website and magazine subscriptions, I cut back on my Kindle habit and started checking stuff out from the library, started going to the thrift store if I needed clothes, started being more aware of food waste and sticking to a grocery list (I was very bad about over buying things and they would go bad before I could eat them). Maybe for you its cutting out getting your nails done and doing them at home.
Step 4. Have A Conversation About Stuff the Family Doesn't Need - This is the easy stuff that you could probably just get rid of but need to check with him first. For us it was a monitored house alarm system we never set, monthly pest control and lawn weed spray service (both of which we could do ourselves in 15 minutes/month), switch to Page Plus Cellular, etc. But it also included some financial things that I needed his input on. For instance, our life insurance needs had changed. As our net worth grew and our expenses went down (less debt) we really didn't need as much coverage. Ditto for auto insurance, we could easily have lowered coverage but just hadn't evaluated in awhile. This is where you really start to challenge not just WHAT you're spending on, but also HOW MUCH you're spending on it. Don't assume that any expense is fixed. Challenge how much you're paying. Once you've evaluated everything, take it to him and say I want to do XYZ. This only took one conversation and he agreed with all my conclusions.
Take a Break - At this point, you've probably shaved several hundred dollars (or more) off of your monthly budget without even really making any tough sacrifices. So give it a rest for a week or two so you don't turn into a money nag.
Step 5. Have the Difficult Conversation - This is where you list all the things that would save you money, but would take a conscious lifestyle change. This could include selling your cars and buying cheaper, more fuel efficient ones. Selling the house to move to a lower cost of living area of the country, or heck just across town to a cheaper house. Cancelling cable, eating out less, going out on the town less, reeling in your spending on hobbies or clothes or food, etc. It helps to limit your focus area. I chose to focus on three our biggest expenditures: sell our expensive car to get rid of the car payment, cancel cable and move to a cheaper house. Over the next few weeks, after the kids had gone to bed, I would casually bring up the pros/cons of one of the items on my list and we'd talk it out over the next few weeks until we both agreed on a course of action. It wasn't done in one 10 minute conversation. It took weeks of evaluating. Eventually, we jointly decided to ditch the car and the cable. Selling the house was a no-go for him and to be honest, I was always on the fence about it. But the main thing was we BOTH agreed to everything after talking it out.
Step 6 - Keep a Punch in the Face List. This is a list of things you KNOW you should do and MMM would definitely do but for whatever reason you aren't going to do. It might include continuing to spend a gazillion dollars eating out, or keeping your pricey house or car, etc. Tape this list to fridge so you have to see it every day. For me, there are things on the list that won't bother me even if MMM shows up at my door. But there are other things that make me wince every time I see it, and that I am sure I will be re-evaluating in the future. And that's the point, to keep evaluating.
So, that's how I got my husband on board. It wasn't that hard, but you definitely can't do what I originally did which was say, "We need to ditch all of our wordly goods, go live like hermits and eat ramen noodles so that I can quit in three years." That would overwhelm even the most reasonable of people. You also can't expect to do it in in one conversation. Lifestyle changes take awhile.
Good luck, let us know how it goes.