I know he's cheating

I have known he's cheating for a while know. Noticed when i was pregnant with my youngest, when i gave birth through till now with a couple of people thats almost 18 months now. I confronted him and he gave me reasons that made me look like am just paranoid but i knew they were all lies. Now last week he came home drunk and i knew something was off. They were together. I know y'all be judging but i still don't want to leave or don't have the heart to leave. I just want evidence that when i show him he will not have excuse to say am paranoid. Thereafter i will tourture him emotionally. I will still not leave i want to see him suffer emotionally. 11 years of waste but just want him to feel how i have felt.