Arjuna had three wives besides Draupadi.
1) Chitrangada - the princess of Manipur. Their son was named Babruvahana.
2) Uloopi - a Naga (serpent) princess. Her son with Arjuna was called Iravan. She also had a big role to play in the up-bringing of Babruvahana.
3) Subhadra - the sister of Krishna - Abhimanyu was born of this union.
Shown above is the painting of Arjuna and Subhadra by Raja Ravi Varma. Arjuna was disguised as an ascetic when they met.