Do you go? This is the time when you use the 80/20 rule. (If the 80 is most of the things you want and the 20 is the bad sex and a few miscellaneous annoyances, keep em).
What do you do? If good sex is high on your priority list and the person is worth investing in- figure out exactly what you want them to do? Initially I advise against a sit down conversation because sex can be a terrible ego bruiser. But instead learn some new tricks and seductively introduce them to your partner. And if they ask why you want to try new things- just say sex with you makes me want to try new things, and leave it at that.Is good sex on my priority list? If good sex is very high on your priority list and you know you can't be faithful while training your mate- MOVE ON... No one deserves to be mistreated and chances are you will never grow to love them- at least not any time soon.
I hope this helps and happy Sexpectating!!!