I think it depends on whether your boyfriend has respect for the Church, even if he does not intend to join it. It also depends on whether he is a Christian at all. It is harder to be married to a non-Catholic Christian than a Catholic Christian, but not impossible. That is why the Church allows it. However, if he is an atheist or another sort of non-Christian, it is much harder. Also you need to get a special dispensation if he is not baptized, in order to be married in the Church.
Lord, please watch over and guide Florence, that she might know and do your will always. Help her to know whether the man she is dating will be a good husband to her and whether they will be able to help each other to increase in holiness, as happens in the best of marriages. When You have let her know your will, help her also to be sure of it so she will not doubt. In the name of Jesus Christ, Amen.
Best wishes,
–Jen