Yup thats the good old gourami..
I have a 5' 100g tank and my male dwarf still chased the female. but with lots of space he hardly ever caught her..lol
I have Oplines, Lace and gold in that tank too, one female and 3 males, all fully grown , and they get on just fine now, each has its own spot in the tank and alls well
I would suggest from previous experience of dwarfs that if the violence is such its distressing, that you should take him out
One dwarf will live quite hapily on its own despite what the Fish shops would have us believe. They go on the fact they keep them in large numbers. Lets face it ,most fish when kept in large numbers will seem to show litte aggression. Ive had several heated exchanges with LFS on this subject, and always ask had they actually kept 2 or 3 in a tank themselves and watched their long term behaviour to each other, the answer is nearly always NO, and a red face is the result.
I would avoid getting another female also,I tried that and it just ment he had more targets..lol and about sent himself dizzy
If youve got a huge tank, you should get away with it long term, but anything other than that means Mrs always gets a good battering sadly