Ok, you can understand it if you take out the adverb ("otherwise"). "I wouldn't have had" is the re-imagined past. The meaning is this never happened in reality - in fact, the opposite happened: "I had these opportunities." If you remove the final "had", then you are in the wrong time-frame.

Hello, I found an explanation on a website : The past conditional describes a past situation that never happened, or it did happen and the person speaking is describing the possibility of something not happening in the past. This is also called the past unreal or the past contrary-to-fact. Here's an example: If I had gone to that party, I would have had a good time. (situation: I didn't go to the party; therefore, I didn't have a good time.) "If I had gone to that party" uses the past perfect in this part of the sentence. "I would have had a good time" is the likely result. Sometimes you can do this without "if" and just use the past perfect: Had I heard the weather report, I would have taken an umbrella. or.... If I had heard the weather report, I would have taken an umbrella. These are both good sentences, but the second one is used more often.

it's "wouldn't have had otherwise"