its up to you what you do, no one can really advise you ..

as you've said you can wait for your appeal or get married.

many appeals are won, it probably would have been better if you had married than applied for a fiancée visa.

but marrying now and applying for a spouse visa after 3 refused visa's you could be refused your spouse visa. if your going to do this, its probably wise to build up a lot more evidence your relationship is genuine b4 you apply.