Wtf??!why is my dad cheating on my mum??!?

[Andrew]

You are in a very difficult situation, you know what you should do as you have mentioned all the options in your question, however none of these is appealing to you for obvious reasons.

I would suggest therefore, just trying to do things that brings you all together as a family, suggest family days out, sit with your parents and hug them, tell them both how much you love them and hope that you will always be together as a family unlike so many other family's from school/church wherever.

If you don't feel confident about broaching the subject with either parent, which is understandable there is not much more you can do but be there for both of them.

But my top recommendation would be to speak to your farther, say you stumbled on the messages by accident and wish you had not seen them but once you saw one you looked at another etc. tell him you love him and want him to be happy but explain how much it would hurt you if he split with your mother and also that cheating on her is just not right.

I feel for you as you have stumbled into an adult problem that you would be better off not knowing about.