Relationships are the easiest thing in the world if you're with the right person. If either of you have to 'try' at any point at all then it's not right.
I've been in a relationship and due to marry this September. We have been together since 2007 and I can 100% honestly say we have not had 1 single argument in that time. Lived together since 2009 and been on a dozen holidays and no fall outs, no arguments, no shouting.
It's very simple. Just respect each other for who you are.
If you love each other, then no need to do anything specific.
Just respect each others views, interests, needs and wants and hopefully you have enough in common to enjoy time together but enough different things to keep it interesting.
Don't complain if they spend time away from you doing other things.
1 thing I will say though as we are no doubt mostly gamers here - invest in another PC / Console / TV etc in another room. So many people I hear having arguments because they are playing games and the OH wants to watch TV.
I've got PS3 in 1 room, PC in another and 360 in another. That way anyone can do anything at any time!!
Just be mature and open
And guys - just because they won't sleep with you twice a day does not mean they don't fancy you as much as you fancy them or that they don't love you! lol