I am having issues with my housemate and his partner. How to resolve?

I moved in with my best friend around five months ago and I am finding it not very pleasant.
I thought it would be a great move, and we get on really well. The problem is that his boyfriend comes round on a regular basis and stays for days at a time. Last month he was here for a week, and the same this month.
I have had to bring up issues about money (as he only contributes £20 a month, and our bills and rent amount to more than £1000), and mess (as he often leaves things lying around the house).
Now I am finding myself not really feeling comfortable and starting to dislike the boyfriend and getting annoyed with my housemate.
When in the lounge, they are often cuddling up, or have their limbs wrapped around each other which I find uncomfortable. I often retreat to my bedroom through awkwardness, and read or watch tv there instead.
I must say that before moving in, I thought I could handle the bf not paying in really, as I genuinely thought he wouldn’t be here that often, so therefore I did agree to that. Now I am starting to regret moving in at all with my friend.
I cannot afford to move out at the moment, and I’m just looking for any advice?