This is my first post and I'm looking for advice. I can take it so be as honest as possible.

To give a brief overview, I am a step-mom of an 11 yr old boy and 9 yr old girl and have a biological son with their father. My baby boy is almost 5 months old. Even though my fiance and I are not married yet, the kids still see me as their step-mom as I have been a major role in their lives for the last 3 years. They are not bad kids. They are normal kids who can get annoying sometimes, but they are respectful. The problem I have is DH's custody is to get the children every long weekend, holidays, and all of summer vacation. I am a teacher so that basically means ALL my vacations involve the kids and if DH is working, they're my responsibility. I no longer look forward to my breaks or summer. Unfortunately, I see having them with us as an inconvenience and more work for me. More laundry, more dishes, more fights to break up, more cleaning, more, more, more.

I LOVE DH more than anything in this world. He is the light of my life. He knows how I feel, but not the entire truth. Recently, their BM and I have made amends and really have been getting along. It's nice. She really wants our relationship to grow and she even bought my son lots of Christmas gifts.
So what is my problem? Why do I feel so annoyed? Does it get easier? Do I ever stop feeling resentful? With DH working alot and traveling out of state, I'm home with them all the time! I usually end up avoiding them as much as possible and being very evasive.

Per my headline title, I feel like a jerk for my behavior last night. It was new years eve and we had a great time at our neighbor's party. We got home after midnight and I was exhausted a still a little drunk. I walked upstairs and DH, SS, SD were all in our bed watching movies of SS as a baby. I was livid! I was tired, wanted to go to bed, irritated that my bed was full of people who didn't care to leave, and watching movies of my DH's previous life. I admit it. I have a hard time with his previous life and don't want to see pictures or videos of his ex. We get along now, but that doesn't mean I want to see her in videos. DH kept asking me "what was wrong" and I should have just said I wanted to go to bed and everyone get out, but I constantly feel like I'm the wet blanket and he's the fun one so instead I did the mature thing (ha). I acted pissed off, didn't pay attention to them or the movie, and waited til they finally finished and went to bed. After it was just us, he asked me what my problem was and I flipped off. The alcohol didn't help. This morning I was upset at my behavior and hope I didn't make the kids feel bad. That was not my intention. I just wish I could find a way to enjoy them more and look forward to their visits. I wish I was not counting down the years til I no longer have to lose my entire summer vacation to taking care of them. Help! I'm tired of feeling this way!