Two things here-
One it's a tricky situation with your finacee and until you're married and the property is legally shared I would avoid having her enter the apartment without you and the tenant being present.
Second-to go along with that, I would triple check your landlord laws and/or speak to an attorney before you, yourself, enter the apartment without the tenant there. Call me a negative Nancy, but if something goes wrong-say a break in and you were the last one to leave the apartment-who's insurance covers it-the tenants or yours? That sort of thing. She sounds like a great tenant and I'm sure nothing bad will come from you helping her out but you want to make sure you're protected. Also, it's a way to cut back on doing those extra things for her if you decide to..."I'm so sorry, my attorney advised that i can no longer enter the premises without you present unless of a dire emergency like fire/pipe bursting etc" that sounds way more professional than "my fiancee wont let me anymore"...and take it from a female...it'll sound better to your fiancee too.