TBH dr alex reminds me of DH! (Also a Dr) I met him around the same age as dr alex is and he had that awkwardness about him-great person, dr and friend. Even on one night out informing me that he didn't fancy me and we would always be friends only!
He had only ever had one girlfriend at that point and was more interested in getting plastered with his mates than he was in relationships.
In the end after several months I made the first move-he definitely made the third! We even split up at one point as "he wasn't sure" though he did come crawling and begging back a few months later!
And here we are, many years and three kids on and very happy together. So no I don't think Alex is gay-he is like many a Dr I have known who have a lot of self awareness and wanting to be a great Dr but no ability when it comes to relationships. I think all credit to him in being honest and telling Alex 3 the truth and I also think she is absolutely fucking marvellous 😍