If I get married, what are my assignment options under the MACP after my delivery and postpartum time frame?

SSG (Join to see) - The MACP is not a silver bullet for dual-military couples. Like many things, you'll be satisfied with the results if you have realistic expectations. The program does have a high rate of success (about four out of every five couples enrolled are able to get a joint domicile assignment), but couples will have to make hard choices that will impact assignments just like they would with other aspects of the military.

If your priority is "stay together", you'll have a lot more success with the program than if it is both "stay together" and "have career enhancing jobs for both of us". Likely you'll have to make a choice as you go up in ranks of "stay together", "be apart so we can both have a job we want", or "you get the job you want and I'll take whatever is available".

Here are a few items that may help you understanding the program better. Make sure you pay attention to the situation you are in (OCONUS on assignment enrolling in the program).

HRC's Website on MACP - if you need further answers from the experts on anything dealing with the policy, follow the procedures at the bottom of the page.
https://www.hrc.army.mil/content/5432

Information paper by the Army G1's office regarding MACP - the last paragraph might be of interest to you.
https://dacowits.defense.gov/Portals/48/Documents/General%20Documents/RFI%20Docs/Dec2019/USA%20RFI%201.pdf

An Army spouse website with some ''non military" views on the program.
https://spouselink.aafmaa.com/married-army-couples-program/

Sit down with your Career Counselor and discuss thus topic. But, know that even if you're enrolled in MACP, there is no absolute guarantee you'd be assigned together. The Army would do its best, but no guarantee.

You can't possibly know what the duty assignments available at that time will be. Those are based on your ranks, PMOS, and duty assignments available when you're both eligible to move. Most of that is subject to change between now and when your future husband will be placed on assignment. What I can say is that you two will generally move together unless one of you is placed on a dependent restricted tour or a broadening assignment like Drill or Recruiting.