Hmmm! Sorry but something doesn't quite ring true with this.He was seemingly ,"almost against his will" in the car with her picking you up from shopping,then went berserk at her when she made the comment about you spending all his money.A bit over the top i think and very defensive,sounds a bit like he doth protesteth too much,i'd watch out to see if he gives her any more lifts.
Hope i'm wrong, i really do ,but an ex partner of mine was seeing a girl at our workplace ,when i confronted her after rumours she blatantly denied it and he went well over the top with his denial explanations.They were both lying.