Is he telling the truth

Hi all...Im posting this because I am so confused!! My boyfriend of 6 years who is my whole life and I love with all my heart, we get on almost all of the time and are SO happy. There have been a few occasions where he has been dishonest but we've worked throught these issues and I have a long history of trust issues.
Here’s a bit of background on previous issues; when we first got together he was sleeping with another girl from work behind my back we weren’t official so I forgave him, he went to Blackpool on a lads night out a few years after we had been together (when we were official) and he got a text from a girl the next day saying ‘'one good sucker’’ I called her to confront her and she was a bit startled but didn’t want to get involved so never gave me the glorious details but I got the gist and forgave anyway cause he said he was so sorry and played it down…most recently last year I have found texts between him and a woman arranging to meet up and being flirtatious…he said she was a ‘rough older woman he had gone on one date with but nothing happened’ – forgave again cause we were having a few issues with our sex life and Id not been feel sexy or comfortable with myself so felt I was partially to blame. There’s been other nights out where he’s stayed out, turned off his phone etc but I had no actual proof for those times but my women’s intuition did tell me he was up to no good. Before we got together he had a 30th lads holiday to Thailand and him and his friends slept with numerous prostitutes – this was before we were ‘official’ so they felt comfortable telling me.
Anyway he goes on a lads holiday to Budapest this bank holiday weekend with some of the guys he went to thailand with he had been drinking all day on the flight back…so he’s telling me about his trip and then I asked where did he stay and he says ‘well the area we stayed was ok but it wasn’t where I wanted to be, I’d done quite a bit of research and wanted to stay in (I forget the name) but our hotel was a 20 minute taxi ride from there’ so I ask ‘ why did you want to be in that area?’ and he said ‘right, when you look it up it’ll say it’s the area for prostitutes but…’ carried on mumbling about a wall and how normal girls aren’t allowed in cause the prozzys kick off but Id stopped listening by this point and went to bed in a mood cause I knew what he’d been up to. I knew he would deny everything and I didnt have any hard evidence just an idea so I decided to check his suitcase in the morning and I found x 2 Viagra jelly sachets in his case…I had previously cleared the case to take away with me so I know it was empty before he packed. Apparently they were for his mate who did sleep with a prozzy but he ‘wouldn’t want to sleep with brass and definitely wouldn’t spend 180 euros like the young dumb and full of cum lads he was with'.
So would you believe him, think he was lying or even if he was telling the truth he’s already messed me around one too many times for me to trust him? We have built such a lovely life together I just wish this type of stuff didnt happen because we could be the perfect couple!!