"I should have spoken to you"
"I should have spoken" to you about the situation
2 Answers
Debía haber hablado contigo acerca de la situación.
I should have spoken with you about the situation.
We could also use...
(Yo) debía haberte consultado sobre la situación.
I should have consulted you about the situation.
"Yo debía haber + past participle..." would start your sentence off as if you should have done something (but you didn't). "el asunto" would probably be better if you mean to say an issue or a topic that you want to "talk about."
Addition: You can use "debería," but you have to keep "haber" with that conjugation because "debería hacerlo" means "I must/ It's a good idea to do it. (now)" whereas "debería haberlo hecho" means "I should have done it. (In the past)"
I was just wondering whether the conditional form would be better suited to convey the sense of "should" ie, "debería".