You fill out the application as a married couple, using joint household income. After you get through you get your eligibility letter (pdf file) which will tell you the subsidy for both of you combined. After that you'll proceed to finding plans, etc. There is a step in there to designate GROUPS. Put yourself in one group, then add an additional group and put your spouse in that one. When you shop for plans it will be for each of you, one at a time. The subsidy will be half for each of you.
We did this last night and then picked the same plan for each of us. So far it looks like 2 individual plans instead of a family plan. I'm not going to call this finished until I get paperwork or emails from the insurance company just because of how convoluted and crazy this was last year. If they put us in a family plan instead of 2 individuals I will cancel the whole thing and reapply and we will pick 2 different insurers just to avoid the family combined deductible.