Larry was dishonest with Suzanne
When Larry had that one sided discussion with Suzanne in the living room of their condo about his expectations for their marriage little did he know what he would set into motion. Suzanne sits stunned and submissive in her chair as Larry tells her what their life is going to be like from then on, attempting to separate her from the dream that has defined her for as long as she can remember. True, Suzanne does everything out of selfish motives, but here we see Larry has been equally false, marrying her without really believing in her aspiration to be a news woman, verbally supporting her in her dream for only a short time, then pulling it away when she feels she might be getting somewhere.
In no way does this justify Larry's murder. As tight knit as the Maretto family is he knew on some level there was not going to be any future plans to move out of state to the big city for Suzanne's career aspirations. He wasn't honest with her from the beginning of their relationship I'll bet. She had every right to feel let down and pushed aside by Larry.
How could he decide, after a year of marriage, that she has had her fun playing the weather girl down at the cable station, and she must now give that up so she could work with him at his father's restaurant?