Thanks again everyone for taking the time to reply.
I am alot calmer now and see a bit clearer. Yes I was wrong for having a major verbal outburst at dh and blaming my period. If I am being honest, I don't usually behave badly with PMT. I didn't abuse him though or use bad language, I just shouted and accused him of something that he feels was totally unacceptable and came out of nowhere.
I do now feel that it's probably my anxiety and panic disorder that is making this all so much worse in my head. My mental health has been deteriorating over the last few months. Maybe my feeling that dh fancied my friend has contributed towards this I don't know. I think at one stage I noticed him enjoying her flirting with him and that set me off on this spiral, then anytime he mentioned her name innocently I was hyper sensitive to it. He probably has mentioned other friends names too but it's her name that I focused in on. This is also probably because I am intimidated by her attractiveness, her confidence and her blatant nerve to flirt with my husband in front of me because in her own words 'thats just the way she is'. It's my own fault for not pulling her up on it when it made me feel uncomfortable at the very start of our friendship. She is a likable person because she is good crack and always has the local Goss. Myself and my husband don't do gossip but when she has all the news on the locals it's fascinating and amusing to listen to, maybe that's why we both enjoyed her company to begin with. I did notice aswell that dh had started to get a bit annoyed with her gossiping at one stage about 2 years ago. He said she is always gossiping about people and it's not right, I defended her by saying sure if she hears it off someone else she's going to tell us, I actually forgot about that until having a chat with dh last night.
So I had a calm discussion with dh last night. I apologised for my behaviour, told him how I felt and why I felt this way. He was genuinely taken aback. He said he definitely doesn't fancy her and listed off a load of things that he doesn't like about her, the gossiping was the biggest thing. In the back of my anxious mind I am thinking is he just saying all these things why he doesn't like her to convince me of it but he really does like her? Then my rational mind believes every word he says.
I know my dh would never cheat on me as far as is possible for someone to know that. Before all this I would say I trusted him 100%. I heard of a time about 8 years ago when dh was on his brothers stag, they all went to a strip club as you do on a stag and those kind of things would never bother me, it's all just fun. But my dh refused to go, told the lads to go on and he went back to the apartment on his own. That always stuck with me, his brother told me this himself one night when he was telling me how envious he and others are of mine and dh's love for one another. We are together since we were 18/19, had first child 3 years later and the rest is history.
I have never felt this way in our 20 year relationship, I have always felt loved and fancied and that my dh was 100% devoted to me so this shook me and I possibly blew it out of proportion. I am thinking now that my own insecurities along with my envy of my friend and her beauty/confidence was the problem to begin with. My jealousy towards her made me project it onto my husband and blow it out of proportion. This worries me about my mental health and I will be seeing my GP this week to maybe start treatment again or even CBT again before I resort to medication.
My friend on the other hand I think needs to go and that's more my fault than hers. I realise I can't handle a friend who flirts with my dh, It didn't bother me before but it does now so for my own sake I am going to just start to contact her less and less. For people asking what her flirting entails, it includes making innuendos about sex to my dh and laughing it off. One night the 4 of us were talking about sex, she brought up her own sex life, my husband said we have a brilliant sex life and she said 'i bet I could still teach you a thing or 2' then laughed saying 'ah I'm only joking' which she probably was in fairness. I didn't just let her away with that though, I just said something along the lines of dh wouldn't need to be shown a thing by anyone cause he gets exactly what he wants at home, that's why we are still together 17 or 18 years later or whatever it was at the time. She brought up sex alot, like asked personal questions about our sex life during pregnancies and how long after birth did we do it etc etc. She was always barely dressed aswell when we arrived after being invited over, one time it was 9pm at night but she was in her bikini, not joking it was actually freezing that night, yes it was summer but I was froze. After a while her dh said to her 'Mary it's freezing would you not go and out something on', she just said 'no I'm roasting'. That night we just ended up leaving after about 2 hours cause it just felt uncomfortable and her dh was pissed off about it and you could tell. There is numerous other things, she'd get pissed and dance around but always tried to drag my dh up to dance with her, not her own dh. Now my dh would be mortified by that and just pushed her away.
I know that is an essay but I am trying to paint a picture for you after you all took the time to reply and had further questions. I know you might think she's not a flirt and I just take her up that way because I am jealous of her but please take my word for it, she is the total definition of a flirt. I found it amusing at first but then somewhere along the line it started to annoy me. Maybe that's how it started for dh too, amusing at first and maybe he enjoyed it but somewhere along the line he thought nah this is not right. There was a time only about 8 months ago where we were invited over, I said it to dh and he said nah rather stay in, couldn't be bothered going over there. I had forgotten about that too until last night.
Again so sorry about the essay but I hope it gives you all some more insight. There is still a tiny niggle in the back of my mind but now I am more interested in tackling my own insecurities and anxieties than I am trying to analyse my dh and everything he has said in relation to this person over the last few years. Maybe he does find her attractive and possibly had a crush on her at some stage but I am pretty sure he doesn't at the moment and if he did I think it would totally stop now because he seen how distressed I got myself over it. He was genuinely horrified that my mental health had started to suffer over the thought of it, he was upset when I said it to him and wouldn't want to contribute to make my anxiety or panic disorder any worse because he has seen how bad I have suffered with it over the years. He has always been so supportive and did anything he could to help me when I was going through a bad patch with my anxiety.
Thanks again for all your replies, I really appreciate it xx