HT: you do need to find a condom solution that works. Otherwise it would be courting disaster. People in open relationships have lower STI rates than people involved in typical garden variety sex behind their primary partner's back because they take the issue of protection seriously. Your writing - great, in theory, but in practice - how would you do all of that without using condoms? Clearly, your partners might themselves have other partners, so there would be a large enough web, raising your risk.

Plus, condoms prevent pregnancy fairly well. So they are, all in all, quite a useful invention.