Confused on ex behavior need advice

So me and my ex broke up she left and started dating some other guy but she still calls me pops up crying telling me she loves me...and all that but on the other hand is posting pics with her new man...so she called me over and after talking we ended up having sex...I know big mistake on me.but today she goes on my page and sees. A girl I posted and I captioned it with heart emojis...she calls asking if that's my girl ect ect then she post s picture of her man with the same emojis...I'm just so confused and wanted to know is she jealous and is that good or will it back fire...please I need some advice