Some of the comments about trusting her etc.. are rather naive given the divorce rate in the UK as a clear indication that even with a legal commitment to each other relationships do break down.
Establishing where you stand and what you could do to protect your interests given it isn't exactly a rare event is pretty prudent.
A friend of mine did see a solicitor before her boyfriend moved into her flat, he signed an agreement with her before moving in. They have since split up and he's moved out and not tried to claim a portion of her flat. If I were you OP I'd go and see a solicitor, spending a relatively small amount up front could save you rather a lot down the line.
Establishing where you stand and what you could do to protect your interests given it isn't exactly a rare event is pretty prudent.
A friend of mine did see a solicitor before her boyfriend moved into her flat, he signed an agreement with her before moving in. They have since split up and he's moved out and not tried to claim a portion of her flat. If I were you OP I'd go and see a solicitor, spending a relatively small amount up front could save you rather a lot down the line.