Curious question: how come people date someone new after their ex pasted away? Like Ariana’s ex Mac Miller died and now she’s with Dalton isn’t that disrespectful?

Hello everyone, so I'm slowly starting to get better in regards to dating. My ex and me broke up cause I just ran away and he had issues too, but he loves me and I love him so we are currently fwb. The issue I'm having is that ever since we dated or I'm trying to get close again; my brain brings up my old ex a lot or another ex. I was wondering if anyone has ever had their OCD use thoughts like mentioning the old ex's name or something against them?

Hey guys looking for some help. I’m so sorry for the long post! Basically I’ve been eating myself alive with guilt and convinced I am a bad person and don’t deserve to be happy ? basically about 5 months ago my ex partner broke up with me. Some stuff had happened in her personal life her mother passed away suddenly and she had also just moved away for a new job - the plan was that I would move in a few months. I’ll be the first to admit prior to theses two events the relationship wasn’t perfect tiffs here and there but nothing major. I thought it was because of the distance to begin with during which time her mother died my partner then came back for a month during this time and understandably was not herself. After a month a bit she had returned to her new home and work. We were keeping up the long distance thing going over phone calls etc but it was hard. She returned for a night out for her bday which I got upset on after some drinks and her acting like she wasn’t really interested in me at all. I had felt like this for a while anyway and was having doubts about moving away. Anyway - about a week later once she had returned we got into an argument over the phone and she said she was sorry she just didn’t feel right anymore about things and was taking it out on me - due to the situation with her mum. She didn’t know how to feel about the relationship and that we would be better off apart - I attempted to salvage things over the phone and was devastated when she said she thought we should end it - she said various things about us not getting on anyway which I thought could be salvaged when I moved to where she was. However she said repeatedly over the phone it’s not going to work and threw in something from over a year ago when I had been drunk and said some things and acted like a dick. Wish I apologised deeply for but I had been upset in general at that time because of some things that she had said or acted when sober. She used this example in why she was breaking up with me. There have been instances where we both drank too much and have said things out of line however I just have this horrible guilt about what has happened each time we were drunk and feel now I don’t deserve to be happy because of my behaviour despite being supportive and willing to move everything for her. I am interested in someone else who I am so excited about and we just click! And I now fully recognise that me and my ex were not meant to be but how the hell do I shift the guilt and allow myself to feel a happy with this other person without thinking about past things said and done? Any help?

Has anyone ever went through grief/a break up where it seems that ocd makes the process worse? Like having anxious/intrusive thoughts that aren’t even reflective of your feelings about the situation?