I don't think I can trust him anymore

Hi all, please be patient with me, newbie on this site as of today. Any impartial advice would be good. My partner and I who have been in a relationship for 10 years now, have hit a 'bad patch'. Bit of background info first, I am in my 40s and he is quite a bit older. We met through our work and when both our relationships / marriages ended we got together. At first, like all new relationships everything was wonderful, life was good. I had a good career and he was self employed. Seven years ago we decided to sell up in the UK and move abroad. Again, life was good, 'living the dream' or so we thought. I was made redundant four years ago and have been unable to secure work since which as you can imagine is getting me down and making me feel totally inadequate. My partner still goes back and forth to the UK to work and I remain at home taking care of things here. The nature of my partners work (construction) means that at times he can be working for private individuals as well as large companies. He has recently carried out some work for a private client (female and of similar age to him). They seem to have become 'close', although of course he denies it. He has even been staying at her home for weeks at a time and not of course telling me. I have seen the text messages between them and they are a little too friendly for my liking for a client / contractor relationship. His excuse for not telling me he was staying there is that he knew what my reaction would be! He tells me that she has other people staying there too. But, like most women, I can sense that he is being economical with the truth. Other problem areas are, he just never takes my side at all. Recently, I had to chase a contractor he was working for as he hadn't received his money for work carried out ( I take care of all the a/cs, well I've nothing else to do) and he completely went off on one saying I had no business chasing this up. Hey, we have financial commitments and bills to pay what am I supposed to do. Anyway, this contractor called me and emailed me and was verbally abusive toward me and my partner did nothing! I then learned that my partner had virtually apologised for me chasing up money that he was owed!! (By the way, the money is still outstanding). Another area is his family (2 grown up daughters and a brother) who will not have anything to do with me. I know as I'm writing this what I should do but it isn't always that easy. We have our home up for sale at the moment but the market is so slow it could take forever to sell, if we did manage to sell then at least it would force us to make a decision about our future (if in fact we have one) either apart or together. I know my being out of work is a huge factor in this, I have too much time on my hands and I'm not used to being dependant on someone else in every sense. But I'm starting to scare myself now as I feel so down and low and can't seem to do anything right, the onset of the menopause isn't helping either. Helpful advice please, ladies would be welcome.