Easy! do not say GIRL/BOYfriend ))))
Let me explain in simple terms. A Temporary Visa to get is means you can prove you are INDEPENDENT and TIED to your HOME country. As soon as you spit the word girlfriend or boyfriend or "friend" of opposite sex that you have been texting each other for the past 20 years on Skype, as soon as you say that - you are DONE.
so would you suggest fiancé (if there really is an engagement) or "significant other"? remember there is proof that kids are involved!