Some people have suffered refusals here and have been persecuted because they are on DLA. A key point to remember is that DLA is used to 'facilitate' - and facilitate is the key word you must use - the receiver of the benefit to live a life more equal to that of abled people.
In a nutshell, DLA helps you keep up with everyone else, just as a wheelchair helps a person get around as quickly as people who can walk and run.
DLA therefore, can be used to help you marry, and live a civil married life, like everyone else.
Basically - when you are using your DLA to help you live your normal life, which includes getting married and starting a family [which you have the absolute right to do] - your use is legitimate and an ECO nor anyone else can argue it cannot be used for that.
I wrote this in an easy format and I hope it helps everyone here.
If you take this issue of facilitation to a lawyer, he will explain it better for you and help you write it into your application or appeal. You can also consult Disability Rights UK for more help:
http://www.disabilityalliance.org/