I'm living alone now..?

Your landlord is probably mainly concerned about the rent being paid on time. I see you live in New York.

At the end of the fixed term of the lease one of three things can happen:

a) The landlord will terminate the tenancy. They generally only do this if they need the apartment for something else (for instance letting a family member live there) or if the landlord was unhappy with you for some reason. The fact that your girlfriend has gone would make no difference to the landlord. The landlord loses a lot of money if you leave and the apartment is empty if only for a week or two.

b) The landlord continues to accept rent, and it becomes a month to month tenancy. In New York once it becomes month to month either party can terminate on 30 days' notice. The problem here is that as far as your landlord is concerned your girlfriend is still a signatory to the lease. So she has the right to move back in at any time. And she might become responsible for any default on your part. And remember she legally owns half the bond.

c) You sign a new lease with the landlord. They will generally do this if you've been looking after the place and paying rent and they don't have an urgent need to use the apartment for some other reason. You'll have to return your girlfriend's share of the bond from your current lease and supply the full amount of the bond for the new lease.

As for living alone, it just means looking after the place yourself. It sometimes means your standards slip with no-one to live up to. For instance, dirty dishes in the sink don't look so bad when they're all your dishes. And it means you can come and go as you please. Living alone is an important stage in finally growing up.

As long as you keep paying the rent, the landlord should be fine with it. I've lived alone for a very long time and I love it. I have the freedom to do whatever I want, when I want.