A short Scriptural comment or passage on any subject should be understood in the light of a larger passage where more explanation is provided.
We ought not to interpret this short statement about "leaving our wives" (Luke 18:29-30) contrary to the statement in 1 Corinthians 7:-
12 To the rest I say (I, not the Lord) that if any brother has a wife who is an unbeliever, and she consents to live with him, he should not divorce her. 13 If any woman has a husband who is an unbeliever, and he consents to live with her, she should not divorce him. 14 For the unbelieving husband is made holy because of his wife, and the unbelieving wife is made holy because of her husband. Otherwise your children would be unclean, but as it is, they are holy. 15 But if the unbelieving partner separates, let it be so. In such cases the brother or sister is not enslaved. God has called you to peace. 16 For how do you know, wife, whether you will save your husband? Or how do you know, husband, whether you will save your wife? 17 Only let each person lead the life that the Lord has assigned to him, and to which God has called him. This is my rule in all the churches. (1 Cor 7:12-17, ESV)
What then does our Lord mean? He is talking about our commitment to Him, which must take precedence over all other commitments, even the commitment to our wife, children and parents. How often when a person is being drawn to Christ will relatives and friends seek to draw him back. Sometimes they will strongly resist, make life very miserable, make threats.
In such cases, in all cases, Christ and our commitment to him must come first.
Christ is not calling us to leave them, but is saying that we must be prepared for them to leave us. And if that is the only way we can follow Jesus then that is the way it must be, as we see from 1 Corinthians 7:15 (above).
Sometimes, a believer might feel guilty that they did not do enough to try to stop their unbelieving wife/husband from leaving them. I'm sure handling these situations is very difficult: it must be very difficult to know what are reasonable, God-honouring, compromises in order to maintain the marriage, remembering what the Lord has said "I hate divorce" (Malachi 2:16).
And sometimes the unbelieving spouse might twist the facts to make it seem that the believer has left them, that it is all the believer's fault. The believer might not be able to be clear in their own minds how much they were themselves to blame. Christ here offers comfort for those who may feel some guilt on account of the separation. Leaving aside how much guilt there is attributable to each party; those who found it impossible to follow Christ until they "left" their wives, etc, will be blessed.
But this "leaving" is never in malice or hatred: in such a case it could never be done for Christ or the Gospel. In the context of Luke 18:29-30 the "leaving" is the leaving of something we would otherwise want to keep, not something we would want to lose.