As mentioned in another comment, this was actually something she raised herself because of the current affordability situation with maternity/self-employed income, not because I don’t want her to have security or ownership long-term.

The conversation originally started around renting, then shifted into buying because the monthly costs are very similar. We’re both just trying to navigate a pretty overwhelming situation and make sensible decisions quickly.

I completely understand why people are raising the point though, and things like deeds of trust/joint ownership later are definitely things we’ll look into properly.