@muri,
It could be that you are pychologically feeling the pressure to orgasm already and it's only making the situation worse.
How about if you if you take the end results out of the equation and you and your partner just agree to stop after that person is satisfied?
Then, maybe you could go into the other room, where you might feel more private, and finish yourself off.
I'm a woman, and I've never had an orgasm during intercourse in my life, and I'm 53. I can and do orgasm with a partner in other ways.
I think when I was young(er) I did worry about it somewhat. Fortunately though, I never bought into that concept that one type of orgasm is better than another type.
I just made it clear to my partners it wasn't going to happen that way, and I've never had one who was so macho that he had to try to make me climax that way to prove something.
If sex becomes more of a chore after so long, it takes away the fun and intimacy.
If your partner is begging you to finish already, I think it will be a great relief to know they aren't responsible anymore for making you climax.