Modeling

I have been in a relationship for over 25 years now. We have both changed through this time and I think I have always tried to accept the changes. We always have done almost everything together. We have a bunch of friends and do some things with them but mostly did things with just us. He was young when we met and he had very few dates before that. My partner is now into weightlifting and has a nice build now. He has also became interested in modeling (mostly nude) and has developed a following on line. He wants to continue with this and wants to travel to parties and such to be the center of attention. I know he loves this and we are monogamous. I do believe that he does not want to do more than show off but I don't like him being around all these people that want to have him. All our plans are rapped around photo shoots and trying to launch his modeling career. Right now we are planning these trip together but he keep saying that at some point he is going to have to go on his own to these. I want the best for him but I get sick to my stomach when I hear about these offers. He just did a photo shoot with someone else. They are sex positions but not sexual. There was hugging but not much more. After he said that he kind of did not like doing this with another person. I was glad to hear that. He also shared an email from the person after that stated that he wish he could have done more sexual things with him. I was glad he shared this with me but I don't like the whole thing. I have always been the type to have one very close friend and now I have continued this with my partner. I feel like I should let this happen and be happy that he comes home to me but the other side see us becoming more and more apart. If he was traveling for a standard job that would be fine but being around all these people that want to have sex with him just bothers me. I have asked for some trips that we can just be together and enjoy things without the modeling and this has not happened. It seems like everything is wrapped around something where is center stage. I trying to be a good sport and be part of this but I have a hard time making this something fun. Not sure what to do here. We have talked about this but he says it is really my problem.