Sex is...
 

You are right. The understanding of what is actual sex is changing, as people are becoming more sexual (compared to years ago). Lots of variations of sex definitions but most have 'intimacy and sexual acts done for pleasure or reproduction'.

Sexual Acts first - I've always thought of it as when there is actual intercourse or penetration of one person to another using their body parts or toys. So I also don't see a hand job, or fondle, or rub, or kiss as being sex. Its sexual in nature, but not sex. But if you stick your finger or a toy or a dick in, now we are talking sex.

Intimacy - Now this is where everything you do with a person that your partner doesn't approve of - is sex. Everything. You were having sex on the phone. Stop having sex with your eyes. That's a sex smile. Why are you smiling.

See, it easy to work out what sex is or isn't. Its whatever your other half thinks it is!