Hi. I really feel for you! Yes an ipod will certainly drown any noise. Some good answers so far, but I just want to add that in my experience it's not purely just having to hear it that's awful! You feel a bit kind of violated and constantly on edge - are they going to do it now, here, there? I should think that deep down you might feel very angry and hurt that your mum jumped straight into yet another relationship and focused on him, instead of giving YOU the attention you deserve. Why should only YOU go out of your way to come to terms with whatever SHE inflicts on your life, and make all the effort to not hear them, when SHE should be making an effort to give you a nice life. Maybe when everything went wrong and it was just you two for a bit, she came to you for love, comfort and sympathy. If it was me I would be livid, and you have a right to feel that way. Maybe, this man offers little or nothing to you as you refer to him as 'a stranger'. Your mum and him should have paved the way for you to bond, and your mum should always put you first.
HOWEVER in all honesty I don't think this will happen, except in a perfect rose tinted view of perfect family life. Your mum loves you very very much but she probably has secretly very low self esteem and therefore she is 'a clinger'. This was probably due to erratic parenting by HER parents. Try reading the book 'They'll F *** You Up' which is a look at the psycology of how we are parented and the effect on our personalities. Interesting stuff.
PLAN 1; Tell your mum how you feel and ask them to be quieter when you are there and save the noisy stuff for when you are not - even the noisiest woman can be quiet out of respect for her children. Tell her to put buffers on - washing machine, tumble dryer, tv or whatever, to disguise the act because you don't want to know it's happening. Does she want to hear YOU doing it when the time comes?
PLAN 2; Get a porn dvd and play it really loud at embarrassing moments for your mum, to teach her a lesson.
PLAN 3; Move out IF and WHEN it is reasonable and desirable to do so (I left at aged 17 and I've had a fantastic and successful life). Maybe that might mean leaving to go and live at university or college accomodation. Your relationship with your mum has got a long way to go yet, and it won't be plain sailing, but it will be easier for you when you are more in control of your environment and life. I'm sure things aren't all bad between you, but sorry to hear about all this.
So, no long term affects from the noise, but possible affects from deeper issues that you have to deal with. It happens to many of us and you'll be a better person for it, but it's a pile of crap at the time.
Be your own best friend - you've got a good head on you, so you'll be a good friend to have lol
Hope the chat works! Good luck!