What she is doing is wrong. Her boyfriend is right to object. You were right to have told her what you did. Stick to it.

She knows how you feel about her. That feeling isn't mutual. She's using you. You probably listen patiently to her in ways her boyfriend doesn't. So she wants to keep stringing you along. She's selfish.

The difference in age between my guy and me is the same as the age difference between this girl and you. So I'm not too concerned about that. But I was older than her when I met my guy.

If this girl is telling you that she loves you, but is not "in love" with you, believe her. It's unlikely that will change. If you care about her, then step out of her life. She needs to finish growing up and decide whether to keep her current boyfriend, or move on without him. She needs to cultivate a female confidant.

Meanwhile, at age 38, you are still quite young, and you need to pursue finding a woman who is truly available to you. I'ld recommend you look at women older than 20. It sounds like you have a lot to offer. Evidently, you are empathetic and supportive. Find someone who has something to offer back.