Seraph was one of the first people Logan was in a long-term relationship with. Marvel Comics readers may remember her from The Uncanny X-Men No. 268. If you read Wolverine Origins, you know their relationship wasn't what it appeared to be.
Seraph was another operative for Romulus. Regardless of what she was told to do, she still loved him. Logan learned her true nature later in life (Wolverine Origins Annual No. 1). This later didn’t alter his feelings for her. He understood that she was controlled just like he was.
8. Silver Fox
Logan's time with Silver Fox had highs and lows. She was the first woman Logan wanted to spend his life with. Thanks to Sabretooth, this was also his original heartache. Wolverine's archenemy slaughtered her and left a note saying, "Happy Birthday" written in her blood. That same pain was amplified by betrayal when she joined Hydra (a moment that may or may not have been real).
For decades, this was the first woman he lost and the beginning of his hatred of Sabretooth. Rose was Wolverine's first bout with heartbreak. However, for decades, he didn’t remember it. Logan knew about his time with Silver Fox. Shockingly, she hasn't come back. Maybe she will be one of the few characters that never come back to life in Marvel Comics.