I'm not really sure what kind of advice to give you there. What, specifically, about the fact that they're both men will make it hard for you to write? And what do you mean by "mature enough" to read it?
I'm just sort of wondering because I'm in the process of writing two stories that each contain same-sex romantic relationships, and it was a lot easier than I thought it would be, no harder than any other romantic relationship I've written, really. Then again, I'm a very character-driven writer and love writing relationships of every kind (romantic, platonic, siblings, enemies, vague acquaintances, you name it) and you said you're more plot-driven, so that could be part of why it's easier for me (and also I don't know the exact beliefs of you and the people around you, but I strongly support gay rights, so that could also have something to do with it, but like I said, I don't know).