I'm blatantly stealing from this
This pretty decent list while adding a few of my own/editing them
First I would like to emphasize and second the importance of living together beforehand as this should be an ongoing discussion and you will be able to answer a lot of these questions long before getting married. Also, if sex is going to be an important part of the relationship it would be a good idea to make sure you're compatable first.
-Do you feel rushed/pressured?
-Why do you want to get married?
- When do you want to get married?
-What does marriage mean to you? Do you think it's outdated?
- What does it mean for everyone's finances?
- Do you think someone should change their name?
- Why do you think people get devorced?
- Will you make a prenuptial agreement?
- What expectations does everyone have of a married life? Roles/chores/behaviors/etc.
- Do you want children? How many?
- Does everyone need their own car?
- What kind of housing is your goal? Where?
- What are important family times to prioritize? Dinner/weekends/vacations/etc.
- Who does what chores, is it equitable?
- Who, if anyone, will be the head of the household?
- Who keeps track of everyone's schedules/doctors/birthdays/friends/family/schools/etc
- Who makes decisions? Personal/financial/familial/etc.
- What is your current financial reality?
- What are you financial goals?
- What are your career goals?
- How will being married affect your finances? Will anyone lose benefits? Will you share health insurance? Will you have split bank accounts? Will you co-sign leases/mortgages/loans?
- Can you afford to raise children?
- Will one person be expected to stay home to raise any children?
- If so will they be compensated? Will their labor be valued?
- Is parental leave a benefit in your current job? For everyone or just one person?
- Sex: is everyone compatible? Is everyone's needs getting met?
- Do you have chronic health conditions?
- Do any diseases run in your family?
- Do you have health insurance?
- Do you have life insurance?
- Do you have a will/end of life plan?
- Are you able/willing to support others through their physical or mental health needs/disabilities?
- Do you want children?
- What makes a good parent?
- What happens if you can't conceive of a child naturally?
- What if the baby is disabled/autistic/gay/trans/not what you expected?
- What will your families think?
- How important are your extended families?
- What boundaries do you want to have with your extended family?
- Can you have close friendships with people you might be attracted to?
- As stated by others: what kind of relationship do you want? Entirely monogamous/open/polyamorous/etc.?
- How much time do you want to spend together? With others? Apart? Asleep?
- Do you actually want to share a bed? A room? A house/apartment?
- How important is religion too you? Do your partners need to gave the same religion? How much/which religion would you want your child raised in?
- How are you planning on sharing you're cultures? What holidays/traditions will you celebrate? With which extended family?
- Same as religion but politics instead
- What values are important to you? What values do you want to teach your (possible) children?
- How will you share your hobbies/interests? Will a specific persons get priority?
- What legal trouble will you be willing to support them through?
- What if you or they end up in jail/prison?
- Should your marriage be valued over other relationships?
Sorry it's so disorganized. Again, just check out the link for a better/longer list. I think it's super important to really analyse what your personal feelings/ideas are about marriage before committing.
Also, divorce is a perfectly good option if it doesn't work out, though it can be difficult financially, which is why it's really important to maintain separate bank accounts and build up enough financial security to be able to leave.
Financial abuse is very real and needs to be considered as do other forms of abuse. Will you have plans to escape dangerous situations? Will you maintain separate support networks to assist you? Will you have someone you trust enough to tell you if you need to get out?
Most of these questions are applicable for any romantic relationship. It's important to go into a relationship being on about the same page, though obviously situations and people change over time.
