Hi users, I need some advice! Please be gentle.
So back in December my OH went out up London for the night with his friends and got really drunk. He went missing that night and no one heard from him until 2pm the next day. His mum was really concerned and text me to ask where he is as well as his sister calling me, etc. We were all quite worried as even his friends didn't know where he was. They said he left them around 1am. I was so worried I logged into his 'Find my iphone' app (yes I know) and saw his location at an address about 15 minutes from home. Very weird. His phone was in and out of 1% battery though so I only saw this once and then it died again. Later on that day he rang me to say he ended up back at one of his mates down the road and just crashed out.
I went to see him that evening and even though I know I shouldn't have I checked his phone and saw he had rang his ex girlfriend for about 10 minutes at 11pm that night before and 2 times again after that. Confronted him on it, we had a massive row and then it got left as he proclaimed his innocence to me and I had no reason to not believe him.
I was scrolling though a Facebook group the other day and saw his ex's sister (I know her through mutual friends) had posted a status about her cat going missing and posted her Street name. Same street that my OH had been on that night. Very weird. To make things worse I then looked her up on Facebook and saw a post she made that read 'Best thing about living opposite XXXX is you can go round for takeaway in your dressing gown' and tagged OH's ex. Confirming that the ex also lived on the same road as the one my partner went missing on the same night he called his ex. All very fishy and I'm now adamant I've been cheated on.
What would you all do in my situation? I've bought this up twice now over the last 6 months and he protests his innocence every time, and we've had about 3 big rows about this but he still says he didn't go back there and nothing happened.

I just need a hand hold really x