meaning of dreams about boyfriend

okay i have been with my boyfriend for about a year now we live together and get along great the only thing is he has two children with a girl he was with since highschool the children are young and we have 100% custody the mom will visit them once a week sometimes twice a week well anyways i know my boy friend would never get back together with her or anything he cant even stand talking to her half the time and i have to encourage him to do so but the thing is i keep having this dream where he takes her side and i wake up very very upset for instance last night im home alone with the kids she comes to pick them up and then walks up stairs and i hear her washing her hands for a long time but i know that she is not washing them she is looking in my bed room and stuff so i get made i am not sure what happens but my boyfriend must come home at some point and he acts like i am the one that is wrong then i had this one where me and my boyfriend are watching a movie on the couch his ex just walks in and sist in front of me so i cant see the tv so im really upset i look back and my boyfriend and he tells me to just let it go so that makes me really mad it just seems like i he takes her side in every dream and i get really really upset about it enough to where when i wake up i am still mad at him.