First of all my boyfriend has never given me any evidence that he's cheating but I'm scared I'm going to get hurt again ( we broke up last year for a long time and got back together 6 months ago ) 

I showed him my downstairs neighbors Facebook account because i was ranting a bout how noisy she was and how loud her boyfriend was 

Then my boyfriend decided he only wanted to see me once a week as he prefers being on his own and time to himself which i agreed to being OK. But then i started getting paranoid that there was someone else and that's the reason why he didn't want to see me more than once a week. Again no evidence to prove he's cheating 

However i started thinking maybe it was my neighbour and that he messaged her etc and now they're having an affair. She told me her boyfriend has gone to his hometown for Christmas And wasn't back till new year and noticed her going out and not coming back till night time ( to add my boyfriend lives just 5 mins down the hill from me. ) several times I've seen her leaving and heading towards his house.  

Last night i was in the kitchen about half 10 at night and i heard her outside her door and another voice so i looked out the window and she was with another guy ( not my boyfriend and not her boyfriend either) and they started kissing and he left so she's cheating on her bf is my first thought 

I told my boyfriend and he said maybe she dumped the other one and i said how would you know that and he got a bit annoyed saying the word maybe was in there

Then he stopped replying to me i could feel myself slowly accusing him and i asked why hed gone quiet and how i was telling him some juicy gossip and he said your neighbour just doesn't interest me. 

Which made me question why has something gone on to make him react like that 

TLDR im really paranoid that he's having an affair with my neighbour. There's no evidence he's cheating and i just want these thoughts to stop 

Can someone advise me on how to get rid of these thoughts i don't want to lose him but i can't shake this horrible thoughts