After being with my DP for 5 yrs, we moved in together last year. This is the first year of doing out taxes as a common law couple.
At the tax office, I joked about how my refund is going to be soo little ($7.90) because my DP will be claiming myself and my children under his. He snidely said, "then file alone." He shocked both me and the tax lady. She piped up and said, you don't want to get caught. I then responded with, why would I do it as single? I have no deductions, as YOU have them all.....mortage, etc.
Anyhow...we did it.
When he got home I mentioned how I think we should open a joint account for the cheque. This way, I can help pay bills, etc.etc. through that. He still keeps his own account, and I also keep my own account.
When cheque comes day after, he makes a comment, "I've got to get to the bank and deposit my cheque". I glared at him and said, thought we were going to open a joint?? He trips over his words and yeah...
At the bank, we open account, and we are standing in line waiting to deposit our income tax into our "joint account". He says, I'm going to put some in there and the rest in mine... I was so mad, upset.
He KNOWS that filing with him I lose $4,000 a year... For income tax he GAINED $4000 because of claiming my family.
I am angry. I feel like he was giving me an "allowance" with whatever he was going to put in our new joint account. He doesnt' pay his bills online, only in the offices, so, it's not like he has bills coming out of his account...
We meet at the bank so I took off...
When I got home, I cut up the new bank card I got, and left it on the table. Not one word from him, as he unloaded crap he bought for "HIS" home...
He clearly saw the bank card cut up. He mentioned going to get groceries and I said, I don't get my money in until Tues, so I can't afford it. He goes to town to do more shopping. Seeing my grocery list I have sitting and was hoping to do....doesn't take it.
Sooo...he banks the $5000 income tax cheque into where ever, and he get his pay check on Fri. Meanwhile, I don't have much money.
I have never, felt like this before. I guess, it makes me thankful, my STBXH, never, ever treated $ that way...or make me feel angry about money...
Next year I will have even more to claim with going back to school and I already dread him taking all of that too... 
Maybe seem petty to some of you who keep separate bank accounts...and maybe you don't have to worry about money like I do.
This is the first year I'm accepting that DP and I are "common-law"...and not a good feeling... 