No, God never stops loving. As I understand what the Bible and Mrs. White teaches about hellfire, this is the very thing that makes hell hell. We, all of us have two attitudes fighting inside of ourselves. The first is the sinful nature or a disposition to think we are for ourselves by making less of the outside world. To esteem ourselves more highly than our breathern, to serve self, to seek the highest place; to serve the lust of the eyes, the lust of the flesh and the boastful pride of life.
But in Genesis 3:15 we received our deepest desire: something in us that wants to be like and with Jesus. To want to love the world as Jesus has loved it.
These two attitudes are fighting in us. We are constantly making choices that places one more in power in our lives and the other less in power in our lives. However, even at our best there is tinged with selfishness, the sinful nature. And even at our worst there is still something there, no matter how perverted, of wanting to love the world as Jesus has loved it.
At the end when "Fire comes down from God out of heaven" it is where the lost see Jesus and God the Father in all their glory and beauty and love. The lost see God and are overwhelmed by God's beauty. Jesus is the one altogether lovely, the desire of ages, great joy to ALL people (not just the honest in heart or good people) the desire of nations, the one beloved of women, the one more desirable than gold and sweeter than the honey.
God's nature is to love them. The Holy Spirit's nature is to point them to the beauty of Jesus. The lost are overwhelmed with this. God does everything short of forcing the will. The lost want to come. They see loved ones they long to be with, and the longing to be with them pales in comparison with their longing to be with Jesus. But Jesus in John 3 says that they are lost because they refuse to come for fear that their deeds will be exposed. They are unforgiving people, and as they see the ugliness of their sins in contrast to his beauty they feel that God can't forgive them and will sooner or later going to get them for their sins, so they refuse to yield to his love and the drawing power of the Holy Spirit. They spent their life resisting the Spirit and this has become characteristic of them and despite their wanting to come, they refuse to come. They want to but they wont. If God was to stop loving them it would cease to be hell and they would just resign to their lot. But it is this stalemate of God constantly loving and drawing them doing everything short of forcing their will and their longing to yield and being so attracted to Jesus, but their refusal to yield that makes this experience hell.