70s SF romance - Similar plot to Eternal Sunshine Of The Spotless Mind

This is driving me nuts today. During the 70's a movie came out that is about a man who is remorseful over a girl he had a loving relationship with. He wants to forget every memory he ever had of her, and even gets help trying to erase them. Just like Eternal Sunshine!
It got a fair amount of praise, but is nowhere near as well-known. I've seen this movie listed on imdb, so I'm not simply dreaming stuff up. Can anybody help me?

I'm sure that this isn't what you're looking for because it's an episode of a TV series, not a movie, but I'm just throwing it out there for you just in case.

There's an episode of the original Star Trek series called "Requiem for Methuselah" where Kirk falls in love, and when he loses her and wants to forget her, Spock erases his memory.

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Yeah, I'm 100% sure that it's a movie since I specifically remember it being listed as one. But sounds like an interesting episode nevertheless.

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https://www.imdb.com/title/tt0063152/?ref_=nv_sr_srsg_3

Found it! The plot wasn't as similar as I recalled and also isn't from the 70's. No wonder it was so hard to find. I'm all good now!