Thanks for your patience.
If your husband is proposing to enter the UK on a temporary T5 visa then you can marry provided that you can provide your identities/addresses and give notice of the marriage to the registry (who will confirm it to the home office)/
However, the barrier to him switching to a spouse visa is that there is a financial requirement, which means that unless you have consicerable savings then you as the UK spouse would have to earn more than £18600 per annum in order for him to apply. The financial requirement is here:
The further barrier is that if he is on a tier 5 visa then he would not be permitted to a spouse visa without leaving the country and applying from his home country.
So, if you marry then he would have to stay on his tier 5 visa until such time as you have upped your salary to above £18600 per annum and then you could apply from his home country provided that you meet the eligibility criteria for a spouse visa which is here:
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