Not necessarily. Needing someone and loving someone are not the same thing at all.
If you can't maintain some degree of emotional stability without being romantically involved with someone, that's a problem. Some people develop an unhealthy dependency on another person to regulate their emotions, but that doesn't automatically make it love, let alone healthy love. It's basically using someone else as a coping mechanism.
Aki "needing" Kei while still being emotionally attached to his late wife and never actually admitting that he loves Kei isn't exactly a positive example of love.
Now, I personally believe that "I love you" can be expressed in different ways, and that not every relationship follows the same dynamic. But that's highly dependent on the circumstances. In this case, the only things that were clearly expressed were that Aki is still in love with someone else, that he's fully aware of Kei's feelings for him, and that he's continuing to get physically involved with him despite that.
Given those facts, I don't think "he needs him" is strong evidence that he LOVES him. Like I said there's definitely feelings, but not necessarily healthy ones.
I guess it’s because I’m aroace so maybe I’m a little different about it because I can experience platonic love and familial love, but when it comes to romantic love it’s a little hard for me to express that in a way. So if I were to express my feelings for someone “I need you in my life” would sound better in my head, but it is different for everyone else!
Lol, I'm actually aro/ace too XD. The funny thing is, I'm the friend everyone comes to when they need to vent about their relationships because they know I'll give an unbiased perspective. I may or may not be a little too direct sometimes, but never in a mean way.
It's easier to have a clearer perspective when it's not your own relationship. I spent so much time trying to understand romantic love in all its forms because I had such a hard time feeling it myself. Eventually, I realized I'm cupioromantic, which basically means I really admire the concept of romantic love. That's part of why I know that no two relationships are exactly the same.
Sometimes I even wish I could fall in love, too. But it just doesn't seem to happen for me the way it does for most other people.

My issue with this is not Aki admitting he still loves his wife since It makes perfect sense. She died it's not like they got divorced or ended in bad terms. He is more than in his right to still have feelings. My issue was how he decided to express it. "I'll be unfaithful to you but I will still take you up on your feelings and touch you" add to this the fact that he never actually told Kei that he loved him or any sort of solid confession aside from I wanting to fuck. Does he like him? he certainly does have feelings for him but they feel more like an enfatuation.