I would first ask if they will marry you. It might be enought that he attends regularly and you visit occasionally. If they will not, you could see if there are any other churches or cute chapels that would allow you to use the facilities. Another option (if weather permits) would be to go with an outdoor wedding of some sort. This way if anyoe has issue with the wedding not being in a church, you can just say that you desired to have the ceremony outside in all of God's glory.