If officer did not pick up on your regular visits without a visa previously u wil be ok . First time they pick up on this it will be a warning to get a visa next trip .. i had this and i know of similar other cases… there is no written rule of number of non visa entries - it is at officer discretion
- if you apply for the visa as i explained above - they will ask for proof that you are eligible to marry !! Bizarre … i just did this and fortunately had that paper with me ..