1. Since you are not applying for a "Joint Loan", and you are using only your income to meet requirements, there should be no requirement for your Spouse to be on the VA Loan Application (which I am assuming you applied for), so as such there should not be any problems at closing.
2. Of course, that said, if you have to use the Spouses income to meet the loan requirements then it will be considered a "Joint Loan" which would mean your Spouse's information would need to be on the loan documentation, and getting married prior to closing may cause an issue that needs resolution.
3. A word of caution, your surviving Spouse whom is not on current loan may or may not meet the VA Loan Eligibility Requirements as stated here. It is strongly recommended that your Spouse be put on the loan at some point prior to the death of the Veteran to avoid any issues or problems.
4. Best wishes on your nuptials.
Hope I answered your question.
Congratulations on your upcoming nuptials and home purchase! Two very exciting life events :)
I recommend calling your mortgage specialist and give them all the details of your wishes. 1-800-531-8722