Now out on bail and working on a farm, Eric McLean's fate will soon be in the hands of a jury.

He's charged in the killing of 18-year-old Sean Powell, the boyfriend and former student of McLean's wife, Erin.

He admitted -- on national television, no less -- that he had shot Powell while the teenager sat in a car outside the McLean's home. But he says he's no murderer.

Eric McLean: (crying) I just feel really bad about the whole thing.

When we sat down with Eric McLean again, two months after the killing, he continued to insist that if the whole story was known, he wouldn't be seen as cold-blooded killer.

He said you have to go back to the beginning.

Natalie Morales: How was your marriage early on?
Eric McLean: It was fine.  It was great.  But -- I mean, we had problems. Mainly just financial problems, but things were great.  We spent a lot of time together and we bought a house, actually before we got married we bought a house.  And so we started, you know, gardening and raise…
Natalie Morales: Raising your family?
Eric McLean: Yes, raising a family and all of that.

But in the last few years, facing the pressures of raising two young sons, family finances, and her graduate study, Eric McLean says Erin began to change.

Having a child at 18, he says, made her feel she had missed out on the best part of her life.

Eric McLean: She just felt like she had lost her youth. And so she blamed me for that. And blamed little Eric for that. It's like we made these decisions together to start a family.

And he says that over the years Erin's frustration would occasionally erupt into outbursts of violence.

Eric McLean: Where I just sometimes would wake up and -- and she was sittin' on top of me just hitting me.  I was asleep in bed.  She just--
Natalie Morales: She physically abused you?
Eric McLean: Yes. And then I remember going to work and they were asking me what happened because I had a black eye. 

About three months before the shooting, Eric began to suspect there was more going on in his wife's life than he knew.

They were at a party and he saw her dial her voicemail.

Eric McLean: And I was just joking around and I told her, "Oh, I saw your password. I know what it is." Because she'd been really secretive about things around this time. When we got home from the party she just went off and started yelling at me and, you know, telling me "You haven't been close to me in a while."  And you can't just, you know, think that you can be involved like that and get in my business like that. And she was just yelling at the top of her lungs. She just told me, "I don't care. You can have the kids, the house, the whole estate. I want my freedom."

Natalie Morales: Is that the first time, though, that she verbalized that she wasn't into this marriage anymore?
Eric McLean: Like that. Where she said that she didn't want anything.  She didn't want the family or anything anymore.
Natalie Morales: Did she ever tell you, 'I don't love you anymore?'
Eric McLean: Uh-huh...
Natalie Morales: How often would you hear that?
Eric McLean: Just when she would have those outbursts and attack me.

That same month the couple had another troubling conversation.

Natalie Morales: What did she tell you?
Eric McLean: She told me that she was thinking about having affairs.
Natalie Morales: And what was your response when she told you that?
Eric McLean: I was just in shock.  Kind of like, "Why are you saying these things and why are you doing these things?"  And she said, "Well, I feel sorry for you because I guess it's because of your Christian upbringing you think that marriage has to be forever."

Around this time Eric noticed that Erin was spending more and more time with a former student named Sean Powell. They spent long hours talking about literature, poetry, music. 

Eric McLean had met the 18-year-old a few weeks earlier when he helped find him a place to live.

At first, Eric thought Sean was just a troubled kid his wife was trying to help.

But his suspicions soon deepened.

Natalie Morales: When did you realize that she was having an extramarital affair with Sean Powell?
Eric McLean: Well, she would tell me things when she was drunk that she wouldn't tell me when she was sober … in a way she admitted it to me at the end of January. But then when she was sober she would deny it.  And I wanted to believe the sober Erin. 

Natalie Morales: Neighbors of yours have said that you would actually go out to dinner with Sean Powell in tow.  You, Erin and Sean.  Why would you let that happen?
Eric McLean: We went out to eat one day after -- early on. This was probably Jan. 5 or 6. I mean,  I suspected things but I didn't know.

Knowing his marriage was in jeopardy and not wanting a divorce, Eric McLean says he just put up with the unusual friendship.

He says he became depressed and sought professional help.

Eric McLean: I didn't feel like I could do anything anymore.  Kind of like I had to force myself to do everything at this point.  Before it -- I kind of had like things coordinated where I could work things out and had almost like a schedule I could follow.  But it was just getting -- some days I just couldn't even get out of bed at all.  And I'd been -- you know.  I don't know.  Every week I started going to the psychologist and psychiatrist every single week.  But nothing ever got better.
Natalie Morales: And she wasn't getting any help as far as you knew?
Eric McLean: No, she wasn't getting any help.

All the while, he says, he was worrying about the toll the situation was taking on their children.

Natalie Morales: What was her relationship at that point like with the kids?
Eric McLean: She treated little Eric horribly.  Just verbally abused him all the time.  But she treated Ian better, but still just neglected both of them.  She just-- basically when she'd get home from work she'd just sit in the bathtub all day drinking whiskey and talking on the phone.
Natalie Morales: Was she talking on the phone with this 18-year-old?
Eric McLean: I guess so.
Natalie Morales: So this time in your life … how would you describe the emotions that you were feeling on a daily basis with her?
Eric McLean: I felt like my entire world was falling apart.  My family was falling apart. I can't even trust her to be around my kids anymore.

In fact, he says his 11-year-old finally confirmed his suspicions about his wife's relationship with Sean Powell.

Eric McLean: He said, "Mom was holding hands with Sean and kissing him and stuff."  And I said, "And how did that make you feel?" and he said, "Grossed out."  And as soon as--
Natalie Morales: How did that make you feel though?
Eric McLean: That made me feel really, really upset.

He says that was a turning point and he began to crack under the pressure.  That same day, Erin asked him to scold the child for being disrespectful.

Eric McLean: She said, "Well, why is he talking to me like this?"  and I said, "Well, probably because he thinks his mom's a whore." I didn't know what to do.  I was just so upset.
Natalie Morales: But yet you stuck by her for another month or so.  You stuck around.  Were you trying to help her?
Eric McLean: Uh-huh.
Natalie Morales: Did you think she would come around?
Eric McLean: I thought she would eventually.

But while Eric McLean still finds it too painful to talk about, friends say he told them he actually witnessed his wife's infidelity with Sean Powell.

Brian Mulkey: He just said he walked in, and they were in the bedroom, and he just turned around and walked out.

By March 9, the night before the killing, the situation at the McLeans' home on Coker Ave. in Knoxville had gone from bad to worse. 

Erin and Sean Powell went to see a play and Sean ended up sleeping over on a couch.

Eric McLean: (emotional) I think just everything when it falls apart … just totally falls apart.