BF has trouble ejaculating

Me and my partner have been together for nearly 3 years. We do not have full sex due to my preference to wait but do have oral sex. Recently he has been having problems with ejaculating and he usually finishes himself off with a bit of help from me but recently he seems to be having problems there too. He is usually quite reluctant to do stuff and I always initiate it (in a non pushy way). We have discussed if he is still attracted to me and he says he is, he is an amazing partner and my best friend. I do not have a problem with him not being able to ejaculate but worry he feels like a let down because of it. He still returns the favour and it is still amazing. Today I said I wanted to treat him (time of the month too lol) and he didnt need to return the favour, today he could not come again. Does anyone have any tips to try and help? We are going away soon and I’m thinking about sexy underwear to try and spice things up. Any help appreciated :)