You can use either address. You want to be able to get mail, if CIC sends you anything, so if you use your Canadian address, make sure there is someone there who can collect the mail for you and forward it. If you want any mail to come to you in the Philippines, then use that address at least as your mailing address. Since the fact you are living with your spouse or partner will help to prove that the relationship is genuine, I would use your Philippine address as your residential address. In any case, you can explain your situation somewhere in the application - say that you have maintained your residence in Canada, but have been living in the Philippines for 18 months on a tourist visa.
Once you have been living in another country for a year, CIC will regard you as not residing in Canada, so you will have to provide proof of your intent to return to Canada with the sponsorship application. For this, it does not matter what kind of visa you are on in the Philippines.
For taxes, to be considered a non-resident for tax purposes, you should be out of Canada for two years or more. You are also supposed to declare this before you go - for example, by canceling your provincial health coverage. Since you will have been out of Canada for less than two years, you can just file your taxes normally. Again, you can use either address - CRA won't care; if they have questions, they will send you a letter about it and you can explain your situation then.