Introductions discussion

Hi Everyone, I’m new to this site but have been lurking for a few weeks:-) I shared with my girlfriend (who lives apart from me) that I want to try chastity play, and she was more excited than I am:-) So I purchased a chrome CB6000 from Lovehoney. It worked okay at first, though my balls were sore initially. I read the forum threads and sanded the inside smoother, but it was hard to sleep with even after adjusting the spacers. I discovered that if I pulled out slightly, things improved, so I tried a KSD3 - no, that hurt terribly! So I sanded it down and gave it another go - better still not great eventually went back to using just a smaller spacer without the KSD3 which was fine until one night when I woke up in pain because my CB6000 had hung from a testicle…the top of the ring broke during the night. So I tried a larger ring and the same thing happened a few nights later:-( My girlfriend also found that with the CB6000 she could f*ck me while wearing it - oh my god - one of the most frustrating experiences for me but apparently very arousing for her:-) So I bought a BON4 and it fits well - holds me in tightly so you can’t pull out but after three days of wearing it, I developed lacerations on my penis and balls:-( So have stopped using that for a while now:-( Lovehoney offered to refund the cost. Looking at what they stock I see the CB3000 which might be an option? I like the BON4 because I can sleep in it - i just dislike the cuts… Would appreciate some advice please:-) If anyone can help me out I don’t think chastity for us will involve her wanting me locked up for extremely long periods because she has a very healthy sexual appetite:-) but maybe for up to a week at a time - but I don’t want pain and need to be able to sleep in it… I am a grower… Don’t want a full blown belt as I have two children who will turn four when she moves in so need something easy to hide… Lots of questions so i hope someone can help:-) All the best Phil