This should be less of a problem than you are allowing your feelings to make it. Peace comes from God and order comes from God. So rebuke the distress. It is not from God. You know that this man is Wiccan. You also love this man. If the love you have for Him is from God you are then also willing to do whatever is best for this man. That means you should be able to leave this man if God calls you to. Has He? If not, stay. The Holy Spirit is not some unclear, guess which way I am going, kind of thing. If you are saved you have the Holy Spirit which can easily direct you wherever you need to go. You know, the only thing you said that set off a red flag in my mind, was nothing to do with your boyfriend but everything to do with the statement, "I could never leave." God is number one. I have had feelings for someone I love from day one, but God has other plans. I am still her friend and would be broken inside watching her get married to another guy if it weren't for the fact that I love Jesus. When it comes to being in the right relationship, even with a Christian guy, it is not about your love or your desires, it is about God. If God wants you to be together, you need to follow God. If God wants you to be separated, you will destroy yourself by holding on. I would, at my level of maturity, stay with the a girl who was doing such things, she would need me there to influence her for the good, but would we get married without her being a born again believer? No. God is very clear. This life is temporary and there are many, many people and good things you have yet to do with your life. This man may be one of them, and might one day be who you are supposed to be with, but for now, ask God, listen to God, wait for the Holy Spirit to keep telling you what is true, and when it is clear, you need to pick the right emotions over the wrong ones. It is one thing to feel love toward someone, it is another thing to actually love them. Do not for the sake of your feelings justify incorrect behavior, such as sex outside of marriage, or anything like that. In the same way, you need to analyze your feelings and separate the right ones from the wrong ones, because it is far more important to be alone than with the wrong person, the person God does not want you with. It seems the problem you are having is you are letting your heart choose, instead of letting God choose, that is why you say, "I can never leave." If God were to call you away from him today with great clarity, could you? If you couldn't you are in the wrong place and far too close to the man. You follow God first, no matter what. I am not saying break up with the man, I am simply saying these things to spark your mind to wholesome thinking. I would stay with a girl doing this because I am mature enough to handle such things without being pulled down, but if God wanted me somewhere else, and to spend time on other things, I would. It is all a part of being who I am supposed to be. You do not know if you will save him and you cannot save him apart from God. Therefor, following God and God alone, rather than your feelings, is going to be how it has to be. If you do not know how to follow the Holy Spirit, simply start spending time alone with God, and listening for Him and reading the Bible. Wisdom will come as you ask for it in your life and you will be able to sense and know what is best. Once again, being in love with someone is not a license to ignore God. If you can honestly tell yourself you are trying your best to follow God and nothing else, and if you continue to do that, I can say you can pretty much live however you want with regard to the rest. But when it comes to relationships, it has to be what God wants. "Whoever is led by the Spirit of God is a child of God." We don't follow our hearts, we follow the Spirit of God. Whether God reveals to you to stay or not, do not let this man bring you down. Allowing this man to bring you down is not love, it is lust.
