Of course you won't know of a gay relationship that has failed simply because of ludicrous claims that they are a sin. In the same way, I have never heard of anyone dying from lung cancer after smoking one cigarette.
I did not suggest that prejudice is the cause of the breakup of gay relationships. They break up for exactly those reasons you mention, which are also the reasons straight couples separate. But straight couples do not have to cope with the additional burden of sexual intolerance fed by ignorance and deliberate misinformation.
It is also extremely parochial for you to imply that your experience of leading an openly gay life is typical. I assume you must have lived in a large US city (such as San Francisco). Try doing the same thing in the mid-west, or Malaysia, or Zimbabwe, or any of countless other places in the world.
You say: "Yes, I know that some gay's have been discriminated against" - "Some" is an interesting (and I suspect deliberate) choice in that statement. To quote from the Scottish Executive: (http://www.scotland.gov.uk/cru/kd01/green/gaymen04.htm)
"In relation to gay men living in the City of Edinburgh the picture painted by the responses to the survey of gay men living in Edinburgh is one of worryingly high levels of violence, harassment and discrimination...57% of respondents had experienced some form of harassment over the previous year". I wouldn't call 57% "some".
Working through a system is fine if you fit into that system. Blacks weren't getting very far until activists stopped playing by the rules that were so heavily stacked against them.
Self-acceptance isn't the issue. Gay men and women that I know, myself included, are perfectly happy with themselves. It's lack of acceptance by others that is the problem.