Feel awful even typing this, and will try and be brief.
For context, I’ve been with DH for 10+ years and we have a 10 year old DC.
Over the past couple of years, when going on outings with friends, I’ve started to feel a certain way about a man that is also at these outings. It started out as just having a laugh, but lately I’m starting to get some intense feelings for him 
I think maybe I’m feeling this way because my relationship isn’t great, and hasn’t been really for a very long time. I’m not attracted to DH, and never have been. However he is a nice man and makes me laugh, and all relationships take work right? If I’m brutally honest I’m starting to find DH repulsive. He doesn’t shower often (2x a week) and brushes his teeth even less, resulting in him smelling bad. He doesn’t wear aftershave either as he doesn’t like it. He has stomach problems so is constantly passing gas, which I know is a normal thing but it’s CONSTANT.
The sex is bad, and he’s a selfish lover. I’ve never had an orgasm with him, ever. To his credit* he does offer to do things to me to get me off, but I don’t want him to touch me - I’m not sexually attracted to him so it just feels weird. If it’s sex as least I know it’ll be over and done with soon and I won’t be pestered for a few days.
I’ve been with him for as long as I have because I do love him, although probably not in love with him. He gets along really well with my family, and our personalities are very similar. He makes me laugh and he’s the one I want to speak to if I’ve had a bad day.
But the attraction isn’t there at all, and he just grosses me out.
I wish it wasn’t like this but it is. I’ve tried for years to get him to sort out his hygiene: withholding sex, being subtle, being blunt. Nothing works.
So back to the other man. It’s gotten to the point where I’m constantly thinking about him, borderline infatuated with him. I want to see him all the time. He’s nice, he smells nice, he’s CLEAN.
I wouldn’t leave DH for another man as that would completely break him, so I feel like I have to stay with him to keep him and everyone else happy. I don’t want DC to have to go through a parental breakup at such a sensitive age either. Plus, I couldn’t afford the bills on my own - I make much more money than he does, but I couldn’t cope financially without him.
I know DH is very attracted to me, and loves me to bits. But from my side it’s just a relationship of convenience, and not hurting him (because it would completely crush him).
I don’t really know what I’m looking for here, I just wanted to get this out to someone as I’m so confused and sad. This is the most honest I’ve ever been about my situation, no one else knows the full extent. It probably seems quite cut and dry from the outside, and if I was reading this I’d be thinking “he’s disgusting, leave him”. But it’s so much harder than that.