Sean- I’ve always been a type b, easy going chap. Like you, a nice guy. But what I quickly learned in my law enforcement career, is that nice guys get quickly walked all over. So, I had to develop assertiveness. Particularly when I promoted to supervisory positions, and eventually police chief.
I was always fair and pleasant, but also no pushover. This assertiveness was not easy to learn at first, but I found people respect it and learn they can’t take advantage of you. You can be a good guy, but still develop assertive skills.
As for friends who don’t reciprocate or have the time for you, have you called them on this? It can be done in a nice way, but if you don’t tell them about your disappointment, they may be unaware and/or never change.
If you have told them, and they still don’t have the time for you, then you must reevaluate the friendship. As Steve Maraboli said:
“Let go of people who dull your shine, poison your spirit, and bring you drama. Cancel your subscription to their issues.”
Hope this helps a bit!