<human>: Can you condense the text into three sentences or less?

My boyfriend James & I have been together for a little over a year & a half. We've had our ups & downs, but overall we're best friends. We share a lot of the same hobbies, values, the sex is fantastic (IMO, I suppose), blah blah blah.

Everything seemed great; but there was a bit of a speed bump. Early in our relationship, he cheated on me with his ex. It was a one-time thing & I didn't find out until months later. I was devastated. This was the first man I ever completely trusted. All of that trust went right out the window. He's tried to regain my trust but quite frankly, he's just not very good at it. I won't go into detail because at this point, it doesn't matter; I'm fairly certain I've made up my mind.

We had an argument once that led to me driving to his house to pick up my things because we were going to break up. I arrived & we talked for a bit, though I asked him to not be there for this specific reason. He begged for another chance. He cried! & that's what got me. I had never seen this kind of emotion from him before.

But now I'm at the point where I need to do what's best for me. This is (was?) the man that I thought I could have built a future with (you know, before all the lies & deceit). But I've seen his true colors. He has a secret Snapchat account & Google searches things like 'I still love my ex after 2 years'. I'm sorry, but I deserve more than just a glorified placeholder.

I guess what I need to know is this: how do I stay strong? How do I tactfully approach this?
<bot>: How do I grow a spine & stick to my guns when breaking if off with my boyfriend? I've tried before, but I must be a jellyfish...