Ill quikly sum this up for you guys:

- Me and my GF broke up for about 2 weeks and got back together after that
- Everything is good again between us
- She had 1 "date" with another guy when we just broke up, she told me they went for a drink and that nothing happened, no kiss, no hand holding, just talking (talking a lot about me aswell)
- After we got back together this guy kept asking her to date again, she said no and he called her a slut
-GF went to party this weekend, saw the particular guy im talking about, gave him 3 kisses (on the cheek) and borrowed money from him for drinks (cause she "lost" her money)

Note: My GF has no money at all and we can't do any fun stuff together unless i pay for it all, i have no problem with that once in a while, but if i have to pay everytime that goes too far for me, and now she went to a party that costed 20 euro (wich she "lend" from a "friend", wouldn't suprised me if she got a ticket from that guy because he was in the party comission) and she borrowed 15 euro from this guy (who called her a slut mind you)

Am i right to be upset or what? And how should i approach this because my behaviour towards her now is really sucky because i feel so upset about this..

I understand being a bit bothered but I wouldn't bother showing it. Maintain the frame of guy who doesn't get jealous at all over small things, thereby reinforcing his frame as loser who calls girls sluts for not going on dates with him and then lending them money.