The nitty gritty of it is, I left my boyfriend back home (in the US), and he left his girlfriend back home (in the DR). I have complete trust in this man, and we are able to freely discuss everything. The problem is that he was dating a girl who is now 17... about to be 18 in 20 days (he is 22).
I was confused when you say he left his gf back home in the DR. Are you talking about your American bf or your current DR bf?.. Your DR bf has this problem or your ex?. If it's your Dominican bf, I agree with the other posters, be firm that you're not going to pay. Tell them to keep you out of it... You should be enjoying each other's company & not be worried or stressed over his drama. I wonder if he's worth it.
Good luck.