Wow sounds like there are and should be some trust issues here. What matters here is that he needs to open up and tell you what is happening in his life. No matter how much you love him, at some point you will need to know what is going on, or the secrecy will destroy your relationship. Once you determine what he is doing and why, then you can make the decision to continue to accept and love him, or you choose to no longer love him and move along.
I do think, you should start insisting that he use a condom when getting intimate with you and he should continue using them until you are sure you are both safe.
I wish you luck on this journey. May you find some peace at the end of it.
