How do you know if your girlfriend really likes and loves you?

I'm just wondering because my girlfriend I know she really does love me but sometimes she does lil things to make me mad then she blames me for it...like two days ago I was having a bad night and she said when I'm frustrated she gets upset...and she is a good girlfriend we love each other and everything and enjoy being with each other but sometimes she does lil things like text some of her guys friends who just want sex and I don't understand that...like she knows what I get mad about and what ticks me off but sometimes I'm like I don't wanna hear about your exs boyfriends or you and your best guy friend went to McDonalds and hung out for a little..I mean I'm your boyfriend and don't like hearing about other guys but other then that she's a awesome girlfriend..we been dating for 2 months...I really do love her...but how do you know if your girlfriend really does like or love you? Signs? sayings? Thanks