I have the same problem and the lady i'm with understands it. We have talked about it and we know that it won't always happen for me but i make sure it always happens for her. This woman is my soul mate and we can talk about any thing and it really helps. The time that it won't happen is going down and the times it does is going up. The best thing is to relax and enjoy. Easy to say hard to do but if she's special she will understand.
you are a smart lady to take advantage.. i dont know why Some women complain either way.. if they dont get enough Or they get too much.. A women should feel proud on their man if she can get couple orgasim every time.. ONce a women have orgasim then she always want one each and every time like a habit.
I also forgot to mention, if you do decide to do what Sammy73 advised, be aware of his reaction, just keep an eye on his body language as you perform, that way you can stop if you think you are going too far with the anal stimulation.
I am going through the very same issue with my boyfriend. He is also perfect for me, except for that one tiny issue, and also as a coincidence, we have been together for only 3 months, and he is also always very tired from work. When I talked to him about it he said it wasn't that I wasn't attractive, he said he didn't know what was going on, but it wasn't my fault and that it was most likely because he was always tired. The sex is great, he always makes sure I am satisfied (which since he doesn't climax, I take advantage of him and have at least 2 orgasms per time we have sex :P ) but the fact that I asked him about him not finishing has made him worried about it so I would say wait until you are both comfortable about the talk...meanwhile do what I do and enjoy :))
severin76 is quite right. I had exactly this issue a couple of years ago, and it still happens occasionally. No idea what started it, it just happened out of the blue, but I do know that worrying about it made it worse.
You could become more involved in his eventual orgasm by fondling or licking his balls and the base of his shaft while he brings himself to orgasm. Some guys can be turned on by fingering around the entrance (or even inside) his anus, but others may be freaked out by it...
I just want to assure you that his inability to reach orgasm during sex with you does not mean that he is not attracted to you or that you are doing something wrong. Some men suffer from this problem, but it is not so well-known as difficulties of women with reaching orgasm (and again inorgasmia in case of women does not have to be caused by the unattractiveness of their partners).
It is possible that this problem will disappear when you have become used to sexual activities together as a couple.
Whether to talk about it with him or not - it is a difficult question, because on one hand it can make him stressed in sexual matters and the more he will focus on this problem, the more likely this ejaculation problem will persist and deteriorate... On the other hand, an open discussion without feelings of anxiety or guilt/shame can bring new insight into the possible reasons and solutions. Maybe later when you are together for a longer time and you get to know each other better, such a discussion may be helpful (if both of you feel safe and secure enough in these matters together).
Meanwhile, I think the best strategy is not to worry about it so much, try not to let this small problem spoil the wonderful experiences which you have together (whether in sex life or in other areas of a relationship), try to focus on all the enjoyable things which sex can bring to both of you. Or you can try to find some professional articles on the Internet written by experts and if the problem gets more serious or if it interferes with your sexual satisfaction (or threatens the quality of your relationship), you can seek for help/consultations with an expert in this field (sexologist etc).
Good luck!