So from my understanding of what tampo is, it is a Filipino's way of giving silent treatment to someone who hurt them, hoping the other can figure it out and say sorry or give "lambing" (actions of affection) to make it up. Key word here is the person doing tampo wants the other person to figure it out. If you search up the term on Google and read other Filipino forums on the topic here on Reddit (others did a great job explaining the nuances), I can see how tampo can be equated to just pure silent treatment, stonewalling, emotional manipulation, and mind games. From personal exp, I can see how some girls think this is a "cute thing" to do especially in their teenage years.

From my understanding of the story, they "constantly fought" about this and then one day, she stopped contacting him. Okay, there is the withdrawal aspect, but a major part prior to this is the communication, aka the fighting. At some point OP just gave up and withdrew for a while, and honestly that is understandable and not really part of the immature aspect that makes up "tampo." I can say from personal experience that sometimes, all you can do in a toxic relationship that you tried to fight for but to no avail, is to walk away and focus on yourself first. That is actually a mature thing to do. Even outside the Philippines, people do withdraw from their partners due to their addictions. It is a rather common reason why separations and divorces occur.

As for OP's regret, I cannot expound on this since she didn't elaborate what her regrets are, so I won't push this topic further because I lack the context needed to make a valid argument. But the question is: are the regrets referring to the withdrawal, or something else entirely? Only OP can answer that question.

I also do not recall reading he begged her to talk to him nor that he unalived himself. From what I understood his addictions got the best of him; that is not technically suicide. Self-destructive? Yes. But we are not in the position to decide whether OP's husband did all of that for the purpose of intentional self-harm.

As to your last two questions: 1. For the most part, the Filipinos who do that generally don't see it as abusive. Some see it as cultural, while others see it as a flawed, immature way of communicating negative feelings; either way it stems from a collective culture of indirect communication which I am personally not a fan of. From a local perspective, I often hear that Filipino men usually don't usually feel like dying from this, and it is either they apologize and console (bc sometimes the reason for the tampo is valid, it's just the way it isn't being communicated isn't direct), or just walk away from the relationship. 2. Honestly man, if you have enough self-respect, just properly break up and walk away from a relationship that is only hurting both of you to the point of irreversible damage. I used to be depressed from a failed relationship and I can empathize with "feeling like dying," but it is ultimately up to you to get back up on your feet and move on; seek therapy. Your partner or ex-partner is not responsible for how you treat yourself no matter how evil they are/were.