"How can money be the root of all evil, when shopping is the cure for all sadness..." Elizabeth Taylor
Could you go into business with your partner? Retail has such a tradition of family owned and run businesses that it almost seems 'normal' to work together. But not every couple can handle the stress of day-to-day contact in a small shop without it taking a toll on a relationship. [I, for one, would not be able to do it...]
Try to look realistically at your relationship, your communication style, and your individual strengths and weaknesses before deciding if you would make good business partners.
One solution to working together is to have separate areas of responsibility and to trust one another to make most decisions within those areas on their own. It may help to divide almost everything into his and hers - even the office files. Do ensure though that you collaborate on all major decisions - even if you don't agree. Try to work out your disagreements in private, however, and present a united front to your staff and customers.