I've had condom-free sex with two of my male partners in the past (one of them was my husband) and it was great fun. Currently, I am not fluid-bonded with any of my male partners, and it's also great fun. I suppose I don't put a high emotional value on fluid-bonding as "the ultimate sexual act", but rather on our sexual intimacy as a whole.
So, while the reasons for fluid-bonding can be important (emotional exclusivity, safer sex, etc.) what I find a more interesting question is what OTHER kinds of sexual activities do people find satisfying and fulfilling? After all, there are so many ways to be sexual and to express intimacy and love with our bodies other than the simple (and rather unimaginative) exchange of body fluid via the penis-in-vagina (or possibly other orifices) sex act.
To address one important aspect of this the topic more directly, I've noticed that my younger male lovers (20's and early 30's) all seem to be much more comfortable with condom use than my older male lovers (40's and upwards). I wonder if this is due to a different safer sex education experience (post-AIDS) or if there are other cultural differences at work?
I personally would NEVER accept the "I can't get it up with a condom on" excuse from a partner. A former partner used that as an excuse to break a fluid bond agreement and it resulted in me mistrusting him (for a good reason, since he promptly contracted an STI). A little lube inside the condom and practice masturbating with one on can work wonders, as well as knowing that you're helping protect the people you love by wearing one. Female condoms may also be helpful in this situation (they work quite well, I can assure you).
I had the very awesome experience of giving an "eroticizing safer sex" workshop at a poly camp several years ago in WA and it was a great way to get people talking, brainstorming and sharing alternative ideas for incorporating sexual health creatively into our polyamorous sexual activities.