<human>: So, a little over a month ago, I met a guy, "Jake", who goes to a college nearby. We hit it off, he asked for my number, and we have been texting constantly. He came and visited me last week, and everything is perfect. He's honestly everything I could ask for in a guy.

The thing is, I "dated" his older brother, "Mark", when I was a Senior in high school for about three months.(So, two years ago. Also, I had NO idea "Jake" is "Mark"'s younger brother when I met him.) By dating, I mean that within three months, we went on three dates. "Mark" quickly got obsessive though, talking about how he loved me, how he wanted to marry me, how we would be together forever, etc. Also, "Mark" never mentioned me to his family, (due to embarrassment because of age difference: 18 and 22, at the time), and so far, whenever "Jake" talks about him, I've acted like I don't know "Mark". 

"Mark" and I didn't end on bad terms, but we didn't end on great terms. He ended up ignoring me, and that's how he "ended" it. We haven't been in contact since it "ended", and I don't have any of his contact information.

"Mark" is not pining over me or anything. He dated a girl for seven months after he "broke up" with me, and is now in another serious relationship that has lasted for four months now. 

"Jake" added me on Facebook, and I can't tell if "Mark" either didn't notice, or didn't care. Since "Mark" kept me a secret when we "dated", I'm not even sure if I should mention anything to "Jake". I don't even consider "Mark" that important, since I only went on three dates with him. But "Jake" and "Mark" are close, and I don't want there to be any bad blood.

What should I do? I REALLY would like to date "Jake" because I see a lot of potential with him.

Give me a shortened version of the text
<bot>: I want to date a guy who I dated in the past's younger brother. I only went on three dates with him, and he kept me a secret. What should I do about the younger brother?