When I'm feeling stressed/alone, I always pick up a book to read that specifically deals with whatever it is bugging me (self esteem, loneliness, relationship dynamics) so although you can't get out a lot because youre the primary caregiver, not sure where you are, but most library systems will let you put holds on stuff from home, and then go pick up a bunch at once, saves time, saves money. Not sure how old your child is but libraries often have story time or other activities for kids, so you could combine it all into one trip if that would be fun for them.
Just sounds like you might want to put more emphasis on being a good partner to yourself than worrying about being a good partner to your husband and boyfriend right now. So I know some people would rather do anything other than read, but it's helped me a lot so thought I'd suggest it, even 5 minutes of reading the right book helps a lot to put things in perspective for me.
Happiness will never come to those who fail to appreciate what they already have.