Indefinite Leave to Remain with criminal past

[ampep]

I got a 3 years 3 months sentence in October 2006 for insurance fraud.

I am to and end of my second 3 year Discretionary Leave (family).

I no longer live with my unmarried partner but live with our children.

Will i be able to apply for an indefinite live next year?

I saw somewhere where it said I have to go 15 years from the date the conviction was spent.

thank you in advance for your responses