You sound like me in many ways - worrying about money even when we are doing "well".
As others have said, it's easy to slide from being "frugal" to being "cheap", often to the detriment of relationships.
What I would suggest is making out a detailed plan with your significant other. Discuss what your financial goals are in the next 1-3 years, and where you want to be in 10 years and 20 years. Is owning a home important? Kids? How secure are your jobs and what's the potential for advancement?
It can seem a bit silly to think that far ahead but it will help clarify why you are saving.
From there you can create monthly and yearly savings goals. There are lots of calculators online which can help you with this.
I find it's helpful to do it both forward and backward - that is, I start looking forward, saying "I know we could save this much per month" and then plugging that in to see how much it would become in 1, 5 and 10 years with projected returns of 4%, 6% and 8%.
Then I 'work backward' by coming up with an amount I'd like to have in 10 years, and then figuring out how much I'd have to save each month in order to reach it.
Then I write down my goals, I automate everything I can (contributions to savings, IRAs, extra mortgage payments, etc) and then I try stop worrying about it. I take comfort knowing I've run the scenarios and I know I'm on the right track. This has been my approach - hopefully it may work for you too.
Finally, in your original post you mentioned you were in your mid 20s but were planning for a 'super-early' retirement at age 55. At least in this forum, retiring at age 55 is not "super-early" - it's kinda on the late side for peope here. If you are indeed saving 50% of your income you should be able to retire in your early 40s. Even with substantial bumps along the way I see no reason why you can't reach FI before you turn 50.
You might want to read this post:
http://www.mrmoneymustache.com/2012/01/13/the-shockingly-simple-math-behind-early-retirement