Just tell your bf that you have realised that you find monogamy boring and ask him if he has started feeling the same way.
Then you will be able to see how sexually compatible you are and if your best option is to end the relationship.
I'm not interested in any type of polyamory, threesomes or fwb.
But I don't share the social attitude that seeks to portray individuals in informal casual relationships where one or all persons are non-compliant with monogamy as 'cheats' in relation to not observing sexual exclusivity.
I believe this commitment and exclusivity comes with marriage/civil partnerships and not casual relationships (like cohabitation, dating, ons, hookups, fwb arrangements, sugar baby & daddy, sex workers).