Ok so I have a male friend, I'll call him X to save me typing my friend all the time!
I apologise for the seriously long post but I'm trying to avoid drip feeding.
So my OH and I have known X for many years, we all grew up in the same village, went to the same school (although not at the same time he is 6 years older than me but the same age as OH), went to the same local pub etc etc.
He has fallen out with various people over the years because he is a very big gossip/stirrer and people obviously don't take too kindly to this including my OH who doesn't have anything to do with him other than being polite/civil if they bump into each other.
He has a really annoying habit of just turning up at my house rather than texting/ringing first - hasn't really been much of an issue up to now as I am rarely in my house and if I wasn't at home he would just drive off, but I go somewhere every evening and X used to go there maybe once or twice a week at the same time as me.
I don't want to state where it is I go in the evenings (it's not a pub or anything like that!) because it might out me but I have to go there every evening at roughly the same time there is no alternative to this incase someone suggestions not going there. I HAVE to keep him on my side for reasons which I won't go into - falling out with him would be serious bad news for me.
So X is single and a few years ago (when me and my OH had just started dating) he helped me out a LOT with different things - I never asked him to, he always just happened to be around when I was struggling with something and this saved me a great deal of effort and time for which I was massively thankful for.
Anyway, he used to confide in me for different things, mainly his love life, and took my listening as a wrong signal and asked me out on a date - I let him down gently by saying sorry you're a nice guy but I only see you as a friend and you're not my type I'm dating Y (my current OH) to which he then wanted to know what Y had that he didn't. Got very offended and avoided me for weeks and made things very difficult for me.
Fast forward to now- he had been relatively normal up to 3 weeks ago, was happy me and OH are still together but had this annoying habit of just turning up to my house every weekend without fail when he knows I'm really really busy and only have a few hours on the weekend to do things I want to do, whether it be cleaning the house or just relaxing for 2 hours max. He would turn up and stay for those entire 2 hours just gossping/stirring and going on and on about his lovelife or lack thereof.
So about 2 months ago he met a woman, turned up and told me all about it, I was genuinely really happy for him and didn't hear from him much during the 3 weeks they were together but then it went horribly wrong he tried pushing it into something more serious really quickly, she freaked out and backed off.
Since then he has been calling me daily/texting me/turning up at my house on a daily basis and going on and on and on about how they split up, insists I read all the messages between them, replays all the scenarios and we have the same conversation every single day.
He he has now met another girl which happens to be an ex girlfriend of my OH from years ago. Told me he happened to bump into her even though she lives 20 miles away and he wasn't anywhere near her home town and then she went back to his and slept together... I find this really hard to believe but that's not the point - he keeps begging me not to tell my OH as he thinks he will get really mad (he won't!) yet rings me to talk about her when he knows I will be with my OH.
He now wants me to go to this girls place of work to "check her out" on his behalf to see if she's his type - I have no idea what his type is it seems to be anyone that will listen to him for more than 5 minutes. I also find it hard to get my head around why someone would need "checking out" after they've already slept together?
I'm getting fed up of him quite frankly, I'm fed up of him turning up unannounced at my house every day - I'm rarely there but my neighbour has told me he has often sat outside for an hour or more and that would coincide with phone calls asking where I was. He waits for me in the evenings at the place I go, and then goes on and on, if I say sorry I'm busy gotta dash he will follow me in the car then go on and on, turns up at my parents house if I'm there.
I work from home twice a week and he came round last week and let himself in because I didn't answer! was most put out when I said I was working and waited outside my house until I'd finished and tackled me when I was leaving the house. And if all of that fails he will ring me constantly. I can't not answer as it might be important and he will start off the conversation with something that seems quite genuine and then ramble on about his love life or start gossiping.
He constantly looks for compliments - sent me a message on FB yesterday which said "oh I don't think I'll be seeing this girl again I'm FAR too ugly" obviously wanting me to say no you're not etc.
Luckily my OH knows what X is like and doesn't seem him as a threat whatsoever but that's not really the point - I wouldn't dream of hounding a male friend if they were in a relationship! OH knows I am in a difficult position with regards to not offending him also.
I think most people in this situation would have asked X to stop this but he gets massively offended if you say you can't talk and goes into a strop and then proceeds to make things awkward for me.
He rang me yesterday, I didn't answer as I was in a meeting so he then text me asking why I wouldn't answer so I said I was busy and what is the problem? He just said nothing is wrong I just need to chat to you so can you answer. I just said no sorry I'm really busy to which he said fine I'll see you later then.
He doesn't seem to get the message, I've tried hiding in my house when he turns up (I really shouldn't have to!) but he will try all the doors in my house, goes round the back, rings me, waits outside etc and its all to gossip or tell me about his latest love conquest and I've had enough. If I say I'm really busy don't have time to stop and chat he won't take this as a hint to leave he just says he will talk whilst I carry on doing whatever it is I need to do. Last week I thought I had found the perfect answer - I said I wasn't feeling well and wanted to just try and have a sleep so he said ok I'll just wait downstairs for you then!
I also feel incredibly guilty as he has helped me out a lot in the past and don't really want that thrown in my face either and I feel like a right cow for not wanting to speak to him all the time when he obviously doesn't have anyone else to talk to.
It's not as if I didn't give him the time of day to start with - when he broke up with the first girl initially I was there for him every single day for 2 weeks, gave him advice which he completely ignored - I told him to delete her from Facebook because he kept checking what she had posted then sent me screenshots and wanted me to analyse it in detail as to what she was trying to say. Apparently " Just popping to the shops with friends" is a cryptic message saying she wants to get back together 
and wouldn't have it when I said it wasn't anything other than just popping to the shops with her friends.
So I need to somehow tell him in a way which won't offend him and make him go off on one, that I can't cope with the daily bombardment of messages/phone calls/ turning up.
Any ideas please? and thankyou for getting this far!