Is it permissible for a husband to host his relatives in his home, which his wife helped build, without her knowledge or consent, knowing beforehand her objection to that?

What a wife spends on building the house has two scenarios: The first is that her intention was to reclaim it or to be a partner, in which case she is entitled to what she spent or ownership of a portion of the house equivalent to her expenditure. The second is that it was given with the intention of a gift and assistance, in which case she has no claim to ownership of the house, but she is entitled to reclaim what she spent, based on the saying of Omar: "Indeed, women give to their husbands out of desire and awe. So, any woman who gives something to her husband, and then wishes to reclaim it, she has more right to it."

If she spent with the intention of reclaiming it and became a co-owner of part of the house, she is a partner, and no one may be housed there without her permission. However, if her partnership is not proven, you may house whomever you wish, and she has no right to prevent you, as long as you have provided her with a separate dwelling.