Found my husband’s prostate massagers and want to join in fun

I’ve been married to my husband for about 10 years and recently came across his prostate massagers. Let me start off by saying our sex life, in general, has been out of this world. We both view it as a mutual adventure. We play with toys, have dedicated sex nights and even go to incredibly hot sex parties where we play with each other and others. Sex is very important to me but it seems like he’s been doing more solo prostate play (I’ve noticed he’s added more solo toys to his collection) and doesn’t ever bring it up with me or ask me to partake. Our sex life has taken a decline too. One time I walked in on him doing it and didn’t make a big deal about. I’m all for solo exploration but – from what I’ve read, prostate orgasms are incredibly powerful – and I want to be part of the fun. I also don’t understand why he is keeping this all hidden away from me when we are pretty open with everything else. I’m not sure what to do. Should I suggest using one of his toys? Should I ask him if I can stick a finger up his butt? Should I bring up pegging? TBH, I’m game for all of that. I really just get off on giving him as much pleasure as possible. I suppose if he only wants to do it in isolation, I should be OK with that but, on a certain level, it makes me a little sad. Looking for advice.