Your business is a disregarded entity and you file it on schedule C in your personal tax return. The "loan" doesn't go on your tax return. It is just a transfer from a personal account to your business account. It's just moving funds from one pant's pocket to the other pocket. It's all personally yours. You just enter the actual expenses you spent it on. So sounds like you will have a Loss on Schedule C which can be deducted on your tax return.
Oh, what kind of business entity is it? If you are a Single Member LLC that is an S corp it is reported a different way. And schedule C is for self employed, sole proprietor, freelance, etc. and not for a joint business. You said "our small business". You might have to file a separate partnership return. What state are you in? I don't know how Married Joint venture works. I'll have to look around for some links.
