Let me get this straight....
1) You've only been dating 5 months.
2) She is a serial cheater who had three affairs (that you know of)
3) Including the now dead ex, this woman has enough emotional baggage for a cruise around the world.
And you want to continue to date her?!? You can't possible be this desperate for a gf.
Are you crazy? She has more red flags than a communist parade.
I'm thinking this is unncessary, uncalled for and inaccurate.
My GF of 5 years cheated on her husband towards the end of the marriage, multiple times. Their marriage had completely broken down, he was abusive, she wanted out, and she, well.. acted out. We sometimes talk about what she did, and I realize that she was in a very bad place with him, it took years to get there and most importantly, he and I are not the same person, nothing like each other so the way she acted towards him has no bearing on the way she acts or will act with me.
To look at a person's history of cheating and say "they did it with him or her, so they'll do it with you!", makes one major blunder. It doesn't include the CONTEXT.
I'll take it a step further and state that I would never get married again, not only because of my past experience including a nasty divorce, but because the legal construct of marriage can trap people in a relationship they cannot easily get out of which makes cheating more likely.
But I digress from my main point which is, he's enjoying the time with her, the intimacy is good or even great despite the fact that GF is suddenly faced with the untimely death of her ex and the associated guilt.
She'll get over it eventually and they could be just fine.
He found someone with whom he clicks, to say he's CRAZY and she's got enough baggage to cruise around the world based on what is written on this thread is extremely shortsighted and presumptive to say the least.