If I recall correctly, Jayce is a mix of two different species. In terms of appearance, he mostly got feline looks from one parent and the stripes come from the other. Can't remember which did he get from who though.
For the parent's relationship, I don't think it's been shown that his parents have a rocky relationship? Other than Jayce's father being kinda an ass to him, that's the most that's been shown about his parents, I think.