Marauders preferences

Your ex he is jealous of

James-Lucius because he hated that Lucius was able to get you to like him and he wasn't able to until fifth year after you became more secure after the abuse in first and second year. Lucius was much older than you and ended up abusing you during your relationship. It was less of a jealousy and more of an anger.

Sirius-Remus because Remus was your first kiss, crush, boyfriend and first date.

Remus-Sirius because Sirius was always his best friend but he always thought that he wasn't good enough for you because of his scars and his lycanthropy.

Severus-Regulus because even though Regulus was younger, Regulus had dated you for a few months.