"...she let it slip that she was pregnant and expected him to get a real job and he flipped?"Now that is a strong possibility! Easy to picture the conversational drift too.
Look, Mark, I was willing to sacrifice and keep supplementing what you earn in your orderly job as long as I thought it was for your plans to become a professional... but we're going to have to support a child soon and I won't be able to work as much for awhile... Mark, you've got to take some responsibility here... Okay, I accept that you're sorry about lying to me and I know you say you want another chance... well, this is your chance to show me you want to do the right thing...Lori, you're right. I'll start looking for another job on Monday -- a full-time job that pays more and I'll start saving up for us. I promise.
...but inside, he's seething with rage and desperate to keep his deceptions a secret from all the other people he's been duping and using. That night, he solves his problem.