This may be moot by now, but I want to address something that I learned, the hard way. The VERY hard way.
If there are red flags before marriage, PLEASE examine and investigate those flags before marrying. Please. For your sake and the sake of any children produced in the marriage. Don't deceive yourself into thinking that it'll all be ok after the wedding. It won't. Seek counsel from those you trust about the red flags (whatever those are; be they religious red flags or something else), and pray for wisdom. And, while I know of stories of unbelieving (or in this case, different believing) spouses later converting, don't bank on that. It can happen, and praise God if it does, but it can also NOT happen.
Faith is a huge issue. It should be a huge issue. If the two parties considering marriage aren't on the same page with faith and how to live it, there are going to be problems that will permeate every aspect of life.
I'm neither pentecostal nor Orthodox, but from what I know of either, they are very very different in all aspects of the faith. Please, spare yourself future heartache and really examine whether this man is truly the man for you, to father your children, and grow old with. Because if you marry, and he becomes resentful or hostile to Orthodoxy, or, God forbid, leaves you over it, the pain and repercussions of divorce are far-reaching and long-lasting.
I say this to try to spare you pain.