Don't fall in love with your Flatmate, don't even pretend to yourself, that you are having a secret de-facto relationship. If an attraction becomes obvious it must be discussed and unless it is agreed that it is reciprocal then "move out".

Someone (and it could be you) is going to be hurt in a big way.

The problems here are many and the outcome will only be tragic. If a relationship may evolve then move out and date.

Don't fall in love with your Flatmates best friend.

Don't assume that your new Flatmate does not smoke dope, fall down drunk or turn into a Casanova every weekend. Ask the big questions up front.

Don't confuse genders! Your Female Flatmate is not your Wife. Many men assume that women must have a "cleaning, cooking, shopping and nurturing Hormone?"

Your Male Flatmate is not your Husband. Many women assume that men love to buy them dinner out and mow lawns and fix cars.

Share accommodation is not about Gender. It is about Fairness, Respect and Consideration. Flatmates should never be put in a position that compromises anyone's trust or safety.