I typed "I have an excellent boyfriend", and it says the correct sentence is "I have a excellent boyfriend". "An excellent" is correct English and "a excellent" is not.
"i have a fantastic boyfriend" not accepted. Add or explain!
It's hard to decide which other adjectives like this choose. But you can easily say 'fantastyczny' in Polish, so...
Ok, I'll try not to translate "wspaniały" with "fantastic" and translate "fantastic" with "fantastyczny" in the normal case.
I think "marvellous" suits.
Ha ha, teach me not to check! I should now always remember that if it looks Spanish, it's marvellous!
I have translated the sentence as suggested but could it also mean just, I have a wonderful boy?
Maaaaaaaaaaaaaaaaybe, but the context would need to make it very, very clear that you mean your son (because that's what you mean, right?). I'd consider it too risky to accept it here.