I always thought Tatum was quite hot too. She is nutty though and I'm not talking McEnroe-level nutty but truly nutty. Other than having a big temper and a big ego McEnroe is fairly normal. Tatum O'Neal, like the others in her family, is pretty far out there.
Years ago I read both McEnroe's autobiography and Tatum's. While of course they both had their own version of their relationship, one sad thing was that when both of them gave their account of their first time having sex they both said they regretted the circumstance. They were both high and they were in a cold house with no heat (Farrah's I think) and it was kinda sad how although both of them didn't like the other at that point they still looked back and regretted being so careless about their first sexual encounter.