FHA: requires the debt of the nonborrowing spouse (even if nonborrowing spouse is not on the deed) be calculated into the qualifying ratios for the transaction. This keeps 'the couple' from over extending themselves.
Conventional: does not count the nonborrowing spouse's debt and allows that spouse to be on the deed as a 'Title Only' status.
FHA is more flexible on the qualifying ratios than conventional finacing (they will allow a higher debt to income ratio).
As always, it is highly recommended that prior to even looking at homes, you consult with a lender and get yourself preapproved. Once you get your financing in place, you will know that you can/will close your transaction.
Happy House Hunting!
I would caution getting married to a home loan if one credit card and only $1,500 in other debt is the difference between you qualifying for a home loan or not.
Just because you may qualify, doesn't mean you should go through with a purchase if cash flow is that tight.