One thing that no one has even touched base on, is soul ties. When you are intimate with someone (and it doesn't have to be full on intercourse), your soul is then forever tied to that person. Most people have more than one soul tie, because even feeling love for someone can tie your soul to that person. I don't kiss boyfriends, because kissing, and the feelings you can develop can turn into a soul tie. I know some people are going to think I'm crazy, but Google soul ties, and you'll find plenty of articles on the subject. Even becoming obsessed with someone can create soul ties.
So, I'm sure you're asking yourself why I'm bringing up soul ties, and how does it have anything to do with your relationship. Well, God talks about how one man, and one woman become one flesh when they are married, their soul is tied to one another forever. When people have pre-marital intercourse, their souls become tied as if they were married, because they engaged in an act that is reserved for marriage. I don't know if you have had pre-marital intercourse, or not, but even if you haven't your soul could be tied to his if you kiss each other, and if you love him. Key word could. I'm not saying for sure your souls are tied, but it's a possibility.
I know for a fact my soul is tied to a guy that I liked a lot, and when we kissed, I knew I gave him a part of my soul. I don't usually let people kiss me, but I liked him a lot. What people don't realise is that, kissing is an act that goes hand in hand with sex. It's intimate, and it is a way to show affection. Many believe it is harmless, but in my honest opinion kissing can open up a can of worms.
Now, even if your soul isn't tied to his yet, if you continue your relationship, eventually your soul will be tied if you have sex with him, whether that is on your wedding night, or not. You need to ask yourself.. "Do I want my soul tied to someone who is committing blasphemy against the holy spirit?" -- By not accepting God as truth, and Jesus as his saviour, he is committing blasphemy against God, Jesus, and the holy spirit. If you were to ever marry him, you have to decide if you can accept the fact that he may never come around. I would hope, and pray that he is repentant someday, but the hard cold truth is that he may not repent for as long as he lives. I'm not going to tell you what you need to do, because ultimately you need to think about what this means for you, what you're willing to endure, and accept, and what you think God wants you to do. We are all human beings on this forum, so we can't relay what God wants for you, because no man knows the mind of God, but you need to seriously pray deeply, and talk to your family, and friends. I would also advise that you talk to him, and let him know that talking about this is inevitable, and at some point you're going to have to talk about it. Don't wait forever for him to talk to you about it, but also give him some time. Maybe he needs time to think, and by pushing the matter on him, you might push him away for good.
From the age of 12-21 I went through a period where I didn't know what I believed. I grew up in a Christian home, and by the time I was able to start wondering what the truth was, I was starting to question if what my parents told me was true. I needed to come to God on my own, and seek the truth on my own. I professed to not believe in God during those years, but deep down I was confused, and conflicted. I think because Gods law is written on our hearts, I knew the whole time that God existed, but all the same I needed to experience life, and come to the point where I chose God on my own, not my parents choosing God for me. So, perhaps your boyfriend is confused, and just wants to come to the truth on his own. I wouldn't be so quick to disregard a relationship of nearly three years. You need to pray to God, and ask for guidance, and you also need to communicate with your boyfriend, when he is ready.. If he dodges the discussion that you know needs to eventually happen, and a long period goes by, and he won't budge, then perhaps that is a sign from God that you need to move on.
All you can do is plant the seed, and God gives the seed light, and water if that person is meant to be a child of God. As human beings there is nothing else we can do, but plant the seed of God inside others, and wait to see if it blossoms. Your seed may never blossom before your own eyes though. You could break up with him, and move on, and years later your seed could finally grow within him. So, don't lose faith that if you don't see your seed grow, that it will never happen, because sometimes these seeds we plant inside of people can take years to grow. I'm not saying you should stick around forever either, waiting to see what happens.
I hope this has provided you with some sort of comfort, and advice that you can use to decide what you need to do. God will guide you, and it's important to heed his words, even if it hurts like salt being poured on a raw wound, and ultimately you don't want to give up your boyfriend. God knows best, and he will show you the way.
God bless, and you'll be in my prayers.