Let me ask is the guy in Nigeria seeking U.S. visa? I am 32,from my experience I had a serious ex boyfriend 28 year old that was horrible in bed but very sweet, caring, and understanding.
I had met a 23year old while I was in serious relationship that was fantastic in bed. He won me over from my relationship this guy lives in different country and I feel he was trying to sell me a dream and do best in bed so I would get him a U.S. Visa. We were working on building a long distance relationship and wanted to get a visa in future. His actions showed me that I was getting set up for failure if I continued to try to bring him to U.S.
He was not mature, he did not know what he wanted but swore he was in love etc to butter me up. Then I found out he was wearing a mask. Social media tells all! I'll leave it at that. I was left with lies,betrayal,low self esteem, etc.

Now I am left to repair and love myself. I am alone I have nobody I got so caught up in this dream that this guy was telling me for reality failure.

proceed with caution with the age diff the younger guy's have the tools to play a game to get what they want! I wish you the best in this. I hope it works better than my experience. I have too many mental problems to go through this.