Wow, thank you all so much for all the time you've taken and thoughtful words, I'm overwhelmed.
I'm at work today so no plan of imminent action, plus his elderly Mum was taken into Hospital the day after Boxing Day and is quite poorly so that is taking up a lot of time running round getting things for her/visits/discussions with Docs etc.
Been together 16 years, not married, no kids (he has two grown up kids from a previous marriage). Completely separate finances. I don't have access to them nor his phone.
We have rented the same large detached house for 14 years, and it is the only place I have ever felt like home.
I was thinking about how I would manage on my own (could just about afford it), and even whether I wanted to stay here with all the memories. In the meantime, DP gets a phone call to say the elderly owner who lived abroad has passed away and the house will be put up for sale. So now I have the added trauma of losing my home. A complication of that is we pay a well below market rent as we do a few jobs around the place. Rents have gone up so much I don't know if I can even afford a grotty one bedroom flat in the same area. If that's the sort of place I end up I will also have to give up my cat who I adore - that really will break my heart. I can't bear the thought of losing him.
I had a feeling all through Summer something was off. He basically lost all interest in me, never talked to me or asked me how my day was etc.
Whilst I was away before Christmas visiting friends I saw pics online of him and her at a local public outdoor event, and I just KNEW then. There was so much intimacy in the body language in the photos. I sobbed my heart out for 2 days.
I casually mentioned on Boxing Day that I had seen the photos (on a local business Facebook page) and asked who she was, he replied 'just some girl that works there'.
On Boxing Day we ended up going somewhere and she was there, DP almost had a panic and insisted we leave immediately (no reason given), and she couldn't take her eyes off me.
I know her name, where she works and that she is single with a 9 year old child.
I am currently in evidence gathering mode, and have already found presents and a note from her to him hidden away, helpfully dated when I was away back in September.
He just randomly announced one day that he'd had an offer accepted on a house round the corner. So he had made the decision to leave, buy, get a mortgage offer, register with local estate agents, go to viewings and then put an offer in, all without saying a word to me. The betrayal is beyond belief.
I will definitely be looking to get therapy once all the shock has worn off. Thank you for reading all this.