I agree with Lillian and others who say as long as it's natural and not planned out. Those that are planned end up stilted and forced and worse the characters involved might end up clicking better with another and then there is ooc drama. I prefer to play it as I would in life, if it works and it is the right time, great. Well done romance can create deeper and more vivid characters and enjoyment for the writers and readers but as it's been stated, it should not detract from the group and the main plot.