Feeling a bit overwhelmed and confused

[raphael]

Hey guys,
My name is Raphael, im a 26 year old gay male living in London,
Born in Brazil and raised in Canada, and have lived in London since I was 19.
Im a very confident, friendly, content person. I live a life where I treat everyone with equity, dignity and respect. I work hard and have made something of myself, for supporting myself since I moved to London.
Also, Im very open and honest, im very close with my family and my friends, wear my heart on my sleeve and like to help people with their problems and just generally be there for the people I care about.
Just a bit of back story there..

Here's where I need some advice.
I struggle to maintain happy and healthy relationships with guys. Im very controlled and like to be in control of my life, so the moment I let someone in, where they could possibly hurt me (emotionally, like break my heart) I start to freak out..
I start to feel guilty for looking at porn, I start to worry what they're doing..
I get upset if I find out they've been with someone I know, things like that..
I get so overwhelmed that I just want to leave the situation. But I cant live like that anymore. I need to deal with the anxiety.

It really hurts me inside to feel like this. I struggle to feel confident and happy.
Note: this has nothing to do with the guys I date, I only date guys who I really care about, I would prefer to be single than to be with someone I dont care about.
So yeah..

Its hard because Im a very intuitive person, I really get myself, and am honest with myself, I would say i know 95% of myself, but that 5% is this weird sexual / relationship stuff, and it seems to take over if im with someone. I used to speak to a sexual health therapist for about a year about it, but decided to end it because I thought I had conquered it, but think im not ready yet.

I have recently started dating someone, we've been together for 3 months, we've told each other we love each other and he's lovely and caring. and understands part of my worries and tries to help. BUT its not his issue and I dont want to impose them on him. Its hard to hear your partner is having problems that are somewhat related to you. Anyways, it kind of hurts that Im dealing with this, and I really care about him so would love some advice so I can get to a good place with myself.

Note: we went to italy together for a week, and i found out that in a previous relationship he was in, it was open, where him and his boyfriend would sleep with other guys together, this really upset me. played on my mind and still does at times. he knows im not into this, the intimacy between us is what turns me on. we got tested together and spend time doing nice things together makes me feel safe and happy and heathy (i value these feelings in general). The idea of anything like that just turns me off and makes me sad. BUT ive also done a lot of stuff in my life, some good and some that makes me really sad, so i cant judge. hes a good person who has a lovely heart, so whatever he did in his past is his business. still, i would love to hear people's views on how to deal with the past.

I guess there's a few things i'd like to ask..

1. I was wondering if anyone else has encountered this? Even if its not exactly the same, would love to hear different views.
2. Has anyone dealt with weird guilt after looking at porn? Like feeling weird or dirty. And its worse when you're with someone?
3. Does anyone struggle with coping with their partners past? Past partners and such. And if so, how did you deal with it?

Thank you guys so much, appreciate any advice.
And if you have any questions, please ask.
Best,
Raphael.