If you're going to pay part of the mortgage please confirm that you are actually on title for the house.  Otherwise, reconsider.  You can pay a general amount towards housing and then spend that on the 'freebies' so DH can see where the money is going.

Yeah, when DH complained one too many times about how expensive things are (both before and after this inflation situation) after going to the store to pick up maybe two bags of groceries of mostly food for only himself and YSD, I decided enough!  We split the standard bills fairly evenly.  He makes more than me, not a huge amount, but enough to be noticable. BUT guess who picks up all the incidentals and household things...you guessed it, me!  Standard groceries, house repair things from the hardware store, cleaning supplies, towels, sheets, misc. things we need - ALL me.

So I stopped buying things for DH and YSD I can easily split out (like no more towels for them...and they are running out b/c DH destroys them by using them in the garage - I have my own stash at this point, no clothes for them, etc.) and the household supplies I make sure I tally up for DH and at the middle of each month he gets an itemized list of the things I've bought that benefit the house as a whole and his 50% cost (note this doesn't ever include things for YSD because I flat out won't buy things for her). This opened his eyes to what I was REALLY covering and he doesn't complain too much any longer.

fail to comprehend that an equity life partnership is not a balance sheet or income statement.

I think testosterone can be an intellect blocking hormone for far to may men.  Particularly those who have brought an X and Kids to a blended marriage.

Equity life partnership is not necessarily about equal income contribution between the partners.  I have been the primary earner for much of our ~28yr marriage.  DW was a SAHM for the first 3 years of our marriage.  I am proud to have been able to provide that opportunity to DW and SS and to myself.  On two notable occassions during economic/industry down turns my DW was the sole income in our marriage. The first was in the early 00s for a year when the semiconductor bubble imploded and I was out of work for 365 days, the second was most of 19, all of 20, and nearly half of 21 when I was on the consulting circuit due to corporate acquisitions and executive restructuring in a series of my employers.  DW nailed it, kept us whole financially, and I am eternally appreciative of her.  I always have been and always intend to be.  Though her covering our life for those periods was a huge help to my career recoveries following those events.  She never once gave me crap for not earning during those events.  I made sure to keep an application, call, job search log daily during those times.  In equal parts due to the need to provide that information biweekly when i submitted for unemployement payments and also do to my internal need to match my DW's efforts when I was her dependent rather than her income contributing partner.

I was raised in a very traditional marriage/parental partnership/family.  Before retirement Dad was the breadwinner paid the bills and managed the finances, Mom was/is the core of the family and has always done it all for the whole family.  An ongoing battle my brother, Dad, and I have with mom is .... STOP!  RELAX! But... she is Mrs people care, craft, gardener lady and continually keeps herself worn out.  Those are the things she enjoys.  All of us, including our spouses and kids consider my parent's home to be .... home. DW and I and SS have lived internationally for many years, as has by brother and his family.  Mom and Dad and their home is the hub for all of us.

I do not recall any time growing up where there was the "I earn and you don't" conversation between my parents.  Interestingly when I was a pre-teen/in my early teens, my parents hit a patch where they were struggling within their marriage.  

Dad pulled me aside and made it clear that if they did divorce he would always provide for Mom.

Fortuneately they weathered that period and just had their 60th wedding anniversary 15 days ago.  I won the parent lottery. The marriage example lottery. The equity life partnership example lottery.

Other than my marital do over, DW and I are doing our damndest to live our own version of what Mom and Dad are living together. So is my brother and his bride.  Mom and Dad just hit 60, we will hit 28 next month, and 3mos later my brother and my SIL will hit 29.

Of course there are no guarantees but it is looking good for all of us so far.

IMHO when it is necessary to provide clarity to a partner, that clarity has to be delivered.

I hope this makes some sense.

but if its him and his two kids and you, then you should pay 1/4 

However as someone else mentioned, it would be good to get your name on the house. 

What has been recommended is that you pay according to ability on mortgage. I dont know what your state laws are regarding ownership of things, but in my state all assets are marital assets. So say he makes twice what you do, you pay according to your earnings ability. Instead of 50/50 you should consider paying 25-30% because no matter what you pay portion wise it is still considered marital assets. Depending. I would nickel and dime things so he can appreciate what you contribute.