I need to live a bit more but cut back too. When we're good about cooking we're really good, but it doesn't last long. I'd like a happy medium between really good food and just basics so that I don't lose the mental energy to meal plan after one week! 
We have National Trust memberships. Not free, but we've been on the under-25's rate for the past two years so under £50 for 2 years membership each, which is great when our local attractions are around £10 each to get into and we could go back again and again!
We'll have to pay full rate this summer, but it'll still be worth it IMO. We're hoping to have enough put aside from bonuses/birthday/wedding/Christmas money by next summer to get a lifetime family membership, so that'll cover us and any kids we end up having :)
We use our NT memberships more when we're on holiday than at home though, we can visit five or six places on a 10 day camping holiday so it pays for itself there.
How old is your DS? Board games are brilliant and you can adapt many to kids. DP and I love Settlers of Catan, Dominion and Carcassonne. I play uno and top trumps with my 6yo and 8yo charges quite a bit too :) I haven't yet got them to have a go at one of my board games but they are interested (every time I've taken my game to work with me their baby sister makes it clear that she won't be left out
)
I'm currently trying to make a list of small things that I can buy in bulk to save money. Things like teabags, which, when bought at £5 for a 240 pack from Asda cost 2.08p each, whereas buying a 460 pack on Amazon at £8.63 is 1.87p each. It's not much but it's just over 50p per 240 bags. DP is a tea monster. We go through a lot of tea.
We save a lot of money by buying our rat food in bulk and making the mix up ourselves too. For a bag (of the type of mix we make) that would last 10 days it's cost us £6, so 60p per day, for me to buy it in bulk and make it up it would work out between 30p and 50p per day depending on what I throw into it. I could get it cheaper to most likely. So if you have small pets it's worth thinking about making up your own muesli style mixes if that's what you buy!
Both of our cars are economical. I have a 52 plate Astra eco and it is amazing on fuel. I'll be gutted the day it dies! DP has just been forced to 'upgrade' as we had a shit situation with a bad dealership. He now has an 07 plate Astra which has some issues, but seems good, also brilliant on fuel. Fuel is a massive expense for us (I have a 12 mile commute to the countryside, DPs commute is 50 miles currently) so to have economical cars cuts that cost a lot. I worked it out to be about 11p per mile between mine and DPs car over one month of usage.
We do have an expensive gym membership though, it's £140pm between us I have health issues and swimming is about the only exercise I can do much of, and a gym membership for me worked out cheaper than going swimming twice or three times a week plus bus travel (our gym is a mile away, so I can walk on good days or park for free on bad days!)