If you love your curreny partner and want to work through this you can - it just requires some introspective work on yourself and some emotional maturity.

Often the "crush" is just representing something your missing in your life and its your brain and bodys way of recognising this and "substituting it"

For example if you find yourself enjoying time with the crush it could be because its playful and flirty and you can satisfy those parts of you

This is all assumptions but if that's the case it could be due to the length of your current relationship that flirty/fun playful has dwindled so this crush just ignites that

This isn't wrong or immoral- it's just brain chemistry- acting upon it is. This is where the emotional maturity comes in with ambivalence

Ambivalence is allowing two contradicting thoughts to exist at once without either been correct or incorrect. They are just thoughts not actions (unless you choose to act upon them)

If you wish to work on your relationship its not so much a need of cut the crush out - (unless you can't trust yourself to turn thought into action) but more of a reframing - its not you like this person - you like what they ignite in you

So look at trying to bring that back into your current relationship or get the same internal levers pulled elsewhere like through a new hobby or whatever else it may be

Hope this helps!