Need advice please

Need advice please

Advice please, it would be greatly appreciated.

So my girlfriend and I have been together nearly 2 years, at 1st the sex was great, she was so outgoing, anal, this and that, even did a bit of camming, had a mfm 3some and talked about a fmf, visiting a swingers club and maybe playing with a couple. She used to give blowjobs in the car and was my personal slut.

Now it's boring. Sex has gone from every day to twice a week. No anal. No car blowjobs, 3some talk is off, swingers club is off. Everything is off.

Is this just normal? Do all relationships fizzle out? She's assured me it's "just the moment," things are busy, etc, and things will go back to how they were.

Is it fair to give 3 months, try my best, make her feel special, and if no changed behavior on her end, then end it?

I don't want to be in a boring sexless relationship at a young age.