Search Results: i worry too much about my girlfriend

ill try to sum it up in as little text as possible,

me and my girlfriend have been together for about 4 years. prior to that, she had another boyfriend and was with him for 3 years. awhile back (september-ish 2016) she said he was sick with some cancerous illness because she saw a picture on facebook about it. that never really bothered her at all. but she told me just recently that his sickness progressively got worse and now he has leukemia from that. i don't know where she heard that or who told her. since she found out, which was about a few days ago, she's been worrying and constantly thinking about him. how do i know? she said "I wonder how (ex bf) is doing with his leukemia? i hope he's not majourly sick", "I've been thinking about (ex bf) lately", etc in a worried/concerned sounding voice. she even tried to convince me to go with her to the hospital to visit him yesterday. should i be worried, or am i worrying too much about this thing? I'm not trying to come off that i want my girlfriend to pay 100% of her attention to me and who cares if her ex boyfriend dies from a bad cancer. I'm just saying that I'm worried she's starting to get more feelings for him again and not have many left for me anymore because of how she talks to him and how she acts around him. also, their break up back in 2014 was mutual. and i know that he still has feelings for her cuz how he is (their break up was not a "he/she did this"). plus, I'm also worried cuz she's constantly wanting to spend time with him again. before she never used to text him or even talk to him and so on. now, she's basically texting him every single day. i don't know if I'm worrying too much, or if i should be worried. i also don't know if this is a jealousy thing that I'm going through. please let me know what you think i should do because i don't want to be stuck in a situation where my girlfriend is gonna possibly be dating 2 guys at the same time if things progress in a way that i don't want them to