I say keep fucking her... do it and enjoy it. Then if you meet someone more interesting... dump her and move on. Took you 30 years to sniff the snatch. If i was you I'd affraid it would take you another 30 years to sniff it again
Just make sure you keep your eyes open.
Or if you dont want to do that make her break up with you. Be somewhat of a dick to her like pressure her into anal sex or be very independent.