You are Moon and he is Venus, ruler of the 11th. The fact that both of you are in the 7th house underscores the problems that concern your friend. It points to the question of how clear the boundaries are between you and your friend in terms of having some other kind of interest in one another besides just friendship.
It does look like he may acquiesce, since Moon and Venus do meet by conjunction. But he does not like the idea, it is against his better judgement perhaps?, since he/Venus receives you/Moon poorly, by detriment.
There also is something off about you/Moon in this matter, pressing him to allow you to massage him when he has reservations, having a girlfriend and all. This is shown by your being Moon in its detriment. And in the house of relationship, not friendship.
So perhaps it might be of value to consider why you want to give this friend a massage if he has reservation about it, that he suggests to you that it may not be a good idea because of his gf.
Like, if he is your friend and he thinks he doesn't want to do it, why would you persist and not respect his thoughts and situation?