"It's not in any way vindictive or an assault on her," Lachey, 32, said in his MTV special, Nick Lachey: What's Left of Me, which aired Saturday. "In a lot of ways, it's more of an assault on me."
Lachey also recently told Rolling Stone that Simpson "blindsided" him when she asked for a divorce and that he doesn't know whether "there were other men."
On whether he could be seen as attacking his ex, Lachey said on the MTV special, "Jessica knows I still love her."
Ironically, MTV first chronicled the couple in happier times – and turned them into A-list celebrities – with Newlyweds: Nick & Jessica.
Saturday's program was in connection with Lachey's new album, set for release on May 9. On it, he sings about the breakup of his marriage on the disc's title track, "What's Left of Me," and songs such as "I Can't Hate You Anymore"
Since the split, Lachey said he's "more guarded. I can't be as open with people because I've been burned."
He went on to say his "biggest fear is being alone" and feeling as though he'll "never find that person that you're looking for, especially when you thought you had it."
But he's still optimistic: "Do I believe that I'll fall in love again one day? I certainly hope so. I certainly hope I'm not going to be the jerk, uncle, bachelor the rest of my life. You know, it's not what I envisioned for myself, but at the same time, when I got married, that was it for me, you know, that was my life."
Last week, PEOPLE reported that Simpson has resumed wearing her wedding ring on a chain around her neck.
"You can still move on and have the memories," a source close to her told the magazine, noting that Simpson still speaks to her soon-to-be-ex-husband. "Nick will always be an important part of her life."