Just need to vent

So I was on MY computer and I usually have my Facebook up and went to my messages and saw that it was my bfs Facebook and messenger to which I saw him talking to a friend (girl) feeling nervous about what was being said so I looked (yeah yeah snooping is wrong) and he was talking about how much weight I had put on and the girl said "well it'll come off in no time since she's breastfeeding" to which he said "yeah but she had him months ago" (3 months pp now 5) and it really hurt what hurts more is he's dated girls bigger than me and he only ever gives me a quick peck when he kisses me I'm really struggling with the weight I live right on the hwy so I can go anywhere to walk unless I drive and we only have one car due to my son's reflux I can't really do Mommy and me workouts I just don't know what to do