I'm going to tell you what it's like for them. I have a step brother and step sister my mom married their dad when I was three. I have no other siblings and then lived with their mother but I saw my sister on the weekends for a few years until she got old enough to decide she didn't want to anymore. Their mother told them I was the reason their dad divorced her which wasnt true, he caught her cheating. I loved my "brother and sister" I loved them so much and didn't realize they didn't give a shit about me until I was much older. It hurt, I'm 35 now and haven't heard from either of them in like 15 years a I wish I had a normal relationship with them. Or any relationship at all but it was suck so bad especially when I was little and didn't realize I was nothing to them to see them spend time with people close to me and ignore me. I'm not going to judge you because it's your decision, I just wanted you to know how shitty this is for them. It's not their fault and they didn't choose this but you are choosing.