Is it normal??

Is it normal to go through phases in a relationship where at times you feel love for your partner but at other times you question if you love them? I have felt this way at times in both of my serious relationships. The feelings are like roller coasters. Up down and all over the place. I don‘ know if it’s just me, the relationship (wrong guy), or normal. It’s extremely difficult to feel this way. I wonder sometimes if there is someone out there who would make me feel always in love with them, or if It’s it just the normal “grass is greener” stuff. Please no harsh comments I just want to know if anyone thinks these feelings are “normal” in healthy relationships.

And in advance thank you so much to anyone who responds. I’d like to stay anonymous on this one.