What you are talking about in your post is not what I would consider to be dirty sex. What is so dirty about kissing?
When it comes to kissing, anything more than a gentle check peck on the cheek is going to involve an exchange of bodily fluids. When you kiss somebody on the lips, there will be an exchange of saliva, which might be minimal, or if the kiss is openmouthed, with an exchange of tongues, the exchange may involve a considerable amount of saliva. Although people get offended if somebody spits on them, saliva is actually quite a healthy substance, and has considerable anti septic properties, as any mum can tell you, when she spits on a handkerchief to clean the scraped knee of her child when it falls over and grazes itself. Spitting itself is seen as practice which is meant to insult, but the actual content that is spat upon somebody is totally harmless, unless the person has some serious infection.
Kissing your partners anus, or licking it could be considered a dirty practice, but it could equally be considered to be showing a really intimate act of love to your partner.
There are all kinds of sexual acts which some people may consider dirty, while others may just consider them to be kinky and erotic. Watersports and scat are definitely two activities which some people consider to be not only dirty, and downright disgusting. But really this is subjective. What one person likes, another person finds distasteful, and as far as I'm concerned, if people enjoy doing something, as long as they're not trying to force it on their partners, and the partners are in wholehearted agreement to whatever is taking place, then I would not consider it to be dirty. Kinky, yes, but not dirty.
For me, the only thing that is really dirty is doing something by force. And that really should be prosecuted to the fullest extent that the law allows. A person who commits sexual assault has no place amongst the rest of us, and should be locked away for as long as possible. No ifs, buts, or maybe's. Not the person away, and make sure that their treatment is as harsh as possible.
So, even if something could be considered dirty, it doesn't mean to say that it's wrong. It is all a matter of what people enjoy doing, and if they are having fun, with someone who is also having fun, then I say go ahead and enjoy it.