I am trying to work out whether...

I think its a bit of both, although primarily cowardice. He's not brave enough to finish with Lizzie properly (although who would be when she's near death like in ep 5?) etc. He is sharp enough to work out what's going on re Ruskin, Millais, Hunt etc, but also to work out what would be to his best advantage. Maybe he doesn't have the courage to finally be a 'proper' rebel and ignore the establishment, he just wants to renegotiate the establishment on his own terms? He does care about people though, he does want fundamentally want things to go well - he just thinks about himself first.

He probably wasn't such a 'bastard' in reality, just a product of his time; selfish perhaps, drama queen maybe, but a true artist all the same. Better than many of his contemporaries who after all, probably wouldn't have even ALLOWED their wives to become artists let alone encouraged them. He was devastated when Lizzie had a still-born daughter and never really got over it according to contemporary letters etc. So not such a 'bastard' then maybe?

There's a saying in the music business of today that unless you're a megalomaniac, you'll never make it. As someone working full time in the arts, I have to convey to you all: being sui generis creative is a really tough way to put food on the table. There are many personality styles people develop in their hopes to succeed: being young, cute womanizers as portrayed in the series was these lads' hobbies, not their job skills. We don't always get it right just out of school...