Help!!!

So I don’t know if anyone else has gone through a stage like this, but atm my partner and i’s sex life isn’t that great. It’s been probably a month or so.. anyhow, I’ve been having all these fantasies of experimenting with a girl (talking to them in a sexual way, seeing where it leads etc etc). I’m not sure if it really means anything or whether it’s just something I want to try because I haven’t tried anything like this to know exactly how I feel..

What should I do?