I absolutely love my step-daughter, I have since the first time I met her when my BF and I got together about four years ago. At first I was the perfect step-parent, baking and doing arts and crafts with her. I taught her how to tie her shoes and braid when her dad couldn't, I just seem to understand her mind more naturally. Then a year or two ago I slowly started to just not be interested in her anymore, and started getting annoyed when she came over for the weekends, and it really messes with me when we have her without warning, which happens a lot since my BF doesn't seem to understand that I like some warning. Something that kind of kickstarted this weird semi-resentment was the almost two weeks the the spring/summer where I had spent months planning a staycation, meditations, at-home EMDR therapy, etc. My BF knew about my plans, but didn't tell me we were going to have his kid for nearly all of it. I wound up spending most of it depressed, helping them clean her room and house, and was too upset to do pretty much anything on my list. I went back to work feeling less recharged than before.
I feel so incredibly guilty, because she got used to me being fairly active in her life early on, a really understanding and patient energy, and now I can barely hang out in the same room as her without my BF. I need way more alone time that never seems to be enough, my temper is shorter, and her normal childlike mood swings and messiness are getting to me more than they ever have. The contrast I can tell has really effected her and her dad. It makes him so happy when I'm a great step parent, but I can't seem to have enough energy for it, which upsets him, though he knows I have mental illness and occasionally physical issues (back aches, etc) that drain my energy, so he doesn't really bring it up unless we're arguing about something vaguely related.
She's the age I was when my sexual abuse started as a kid, and since some stuff has cropped up about that within the past year my mental illness has gotten worse; my BF has withdrawn which makes me withdraw which makes him withdraw more and makes me feel drained; I desperately need to recharge; I love her so much that I resent her mom (who is a terrible person but is getting better with time and her current boyfriend) for having her because I will never have a claim to her, I will never have a right to love her, and I will never have a right to discipline or teach her the way I think a kid should be.
She really is a great kid, so funny and smart and sweet, I just cannot seem to find my love energy for her and I worry it's going to mess her and my relationship up forever.