HELP!

I have a 5 month old and two stepsons. When the step kids come to stay I feel like I have to hold him constantly as they want to play with him or pick him up and it can get a bit rough/im scared they’re going to hurt him accidentally. This is making it stressful for me as I can never relax and my husband isn’t much help - if I need to run upstairs or leave the room quickly ill ask him to keep a close eye on the children and he’s so much more relaxed he doesn’t really. Has anyone for any suggestions of how I can relax a bit or anything that will help because at the moment I’m dreading them visiting and I don’t want this to continue. Thank you all.