Hi Anna,
I believe you are correct, the time where tourist status will be rejected is very close.
You do need to secure a long term Visa.

Please take a look here:-
http://www.ukba.homeoffice.gov.uk/pa...mesexpartners/

The requirement that you really need to comply with is:-
You have both been living together as if you were married or in a civil partnership for at least 2 years; and
You both plan to live together permanently.

Discuss with your b/f how best to comply.

All members here will offer support and ideas for you.