I feel for you as it sounds like you give up alot for your partner. Here's a few thoughts that might help :
- Explain to her that guys need hobbies, its a fact of life and rc is yours and will be for a long time. If she wants you to be happy (and all partners should) then she will accept it and respect it.
- Try to plan ahead and organise. If she likes to catch up on telly on sunday, plan with her that you will be tinkering on rc. You can try to set up your table in the same room as the telly so you can still be spending time together and talk etc.. Also stop and have lunch or breaks together.
- Move into the house asap. Whatever problems your shift work might cause it sounds like your life would be much easier if you stopped renting. You would save money and see your partner and her children more, hopefully making them less desperate for your attention on the weekend.
Hope you sort it out