Upvote:5
A marriage visitor visa is only appropriate if you intend to leave the UK again afterwards - see the third bullet point on the linked advice. For your partner to live with you in the UK would require a family visa but that is more of a query for Expatriates.
If your partner has difficulty getting a UK visitor visa, you could go to Russia or arrange a joint trip to a third country.
Upvote:7
There seem to be two problems here.
In my opinion, if you are serious about this relationship you need to start seeing each other, both to satisfy the authorities that your relationship is genuine and frankly because a Marriage or Civil Partnership is a long term commitment that you shouldn't rush into lightly.
I am not an expert but I doubt a single visit will be sufficient to establish a genuine relationship. I expect that to avoid serial refusals it would be a good idea to talk to a lawyer before making any further UK visa applications.
If your proposed partner can't get a Standard visitor visa to the UK then it seems like your only real options are to either meet with him in Russia or meet in a third country.