My reading is that this is the sequence of events from his POV:

1. He had said that she couldn't live with him, but they were still dating.

2. They have a big argument, she stabs him in the chest.

3. He goes to work, says if he doesn't show up the next day she killed him. Coworkers veg him not to go home, but he's worried about his kids.

4. He goes home to find that his kids are sleeping over at a friend's house. He hangs out with neighbors (probably to stay out of the house) until 11:00, when goes to bed.

5. She wakes him up an hour or two later with lingerie and (presumably) and "I'm so sorry, let's have makeup sex".

6. He wakes up after getting stabbed in the chest a few times, turns on the light to find that he's bleeding, tries to make it out the front door, but either falls or is pulled back inside and dies from blood loss.

On the whole, I'd say his actions were only foolhardy with the benefit of 20/20 hindsight.