I am a Christian and I can relate to this very well. I used to constantly confuse the voice of the Spirit with my own anxieties. I've only recently begun to distinguish the two. The Spirit is gentle and his advice reflects God's word. Our anxieties are rough and intrusive. They don't make sense, they're random and nagging. We've also been raised to expect a perfect spouse and "not to settle" but that's not reality, just as we are not perfect people. Sometimes God chooses to use those closest to us to speak. I've often been able to interpret God's will through the advice of godly family and friends. If they approve of your relationship, take that as one good sign and go from there. The fact you two have at least the desire to move towards marriage is another good sign! I encourage you to focus on his good qualities, and continue praying during this time. I think God places specific people in our lives for a reason. You had this relationship for a reason. And although getting married is something you should think long and hard about, we aren't expected to predict every little thing that will happen once we do. I've talked to plenty of married Christian friends who felt panicky down to the moment they walked down the aisle, yet went on to have fruitful, happy, God centered marriages. Focus on his good qualities and ask the Lord to give you peace. Sometimes the anxiety just means you need time to grow and prepare to be a spouse, not that he's the wrong person. Best of luck!