I need advice.

I asked my boyfriend to tell me one thing he's never told anyone. He didn't reply at first but the next night he text me and said "I have an answer for the question you asked me". So I said "ok baby what is your answer." I don't know what I was expecting him to tell me. He told me he enjoyed wearing women's clothing and that it was a turn on for him. That doesn't bother me. I'm a very open minded person and something like that really does not bother me. I still love him because he still the same person no matter what clothes he is wearing, BUT, I don't know how to react. He started to put on my outfits like my little schoolgirl uniform that I got for us in the bedroom he started to wear my underwear and he sent me a picture of him wearing my pants. I don't want him to think that this bothers me because it doesn't I just need some advice because I I think he might be bisexual. My reasons for thinking this is because I got on his Tumblr just because I wanted to get on Tumblr and I don't have one and it was full of women with penises (mind you this does not bother me ) The thing that bothers me is he was messaging someone on Tumblr and had them send Dick pics to him and he sent one to them and he told them that they had a very attractive penis. The person continued to say that they would come and visit him and that they could meet up and have sex. He replied with "I really don't think I could cheat on my significant other (me) especially with someone I don't know" that was on the 28th and they haven't talked sense but I still don't know what to do. Can someone please just throw some ideas out there because I love him I really really do but I don't know what to do.