Partner lied to me - where do I go from here?

Going to try and keep this as brief as I can.

I was helping my partner sort through his paperwork for tax, as I do every few months. When I got to his November bank statement I saw some payments for a club in the location he was staying for work. I thought maybe he’d mentioned he’d been for a night out with his work friends and I’d forgotten, so I scrolled back in our messages but on that night he sent a picture from his bed at 11pm saying he was going to get an early night.

I asked him about the payments and he said that the club was promoting at the venue he was working at so when he’d got a drink after work that evening it showed up as something different on the statement. This made no sense so I pushed again and said the till would still show the same name as the venue even if they were selling their drinks. He said ‘I swear on my life I didn’t go out.’

I said it didn’t matter if he did I would just like him to be honest. He said he had a few drinks but he definitely didn’t leave the venue he was staying at. I could see on his face that he was lying but he was adamant.

I said ‘I don’t know what reason you would have to lie, and I know it’s really hard to backtrack once you’ve started spinning a story, but I’m giving you a free pass here to just admit it because I would really appreciate your honesty.’ He said ‘yes I went out but I didn’t go far and I came back alone.’ That really shook me because it didn’t even cross my mind than he wouldn’t have. I asked him outright if he went to that club and he said yes. He said again ‘nothing else happened though’

I asked why he just lied to my face and he said he panicked because he thought I’d be angry. I said I’m not angry he went out but I’m angry that he lied. He swore on his life and looked me in the eye and I nearly believed him. I said what else have you done that you haven’t told me and he said absolutely nothing … but now I feel I can’t trust anything he says.

Now he’s saying ‘See I knew this is how you’d react which is why I didn’t tell you.’ Is this a relationship ender? We’ve been together 5 years and are engaged - I’ve never had a reason not to trust him before and this has really shook me. I’m doubting everything. Please advise where to go from here.