If you and your partner are in a registered domestic partnership (RDP) and you reside in the community property states of California, Nevada, or Washington state, you'll each need to prepare your own federal tax returns based on your state's community property rules.
You'll both report your share of community property income, which is determined by your state's tax laws and other factors like prenuptial agreements.
We can't figure out what your share of community property is. Each couple will need to determine this for themselves. IRS Publication 555 (page 3 in particular) has guidance on how to determine and properly split community income.
Tip #1: Let's be honest: understanding community property tax laws and calculating each partner's allocations is not something most people enjoy doing. You may want to engage the services of a tax expert or CPA who specializes in community property tax preparation.
Tip #2: If you choose not to follow tip #1 and you also want to jointly file your California state return, we strongly recommend switching to the TurboTax CD/Download software instead of TurboTax Online. It simplifies things and will also saves you some money. Additionally, our instructions in Part IV are geared towards the software.